I thought I'd revive this idea and see if we can get some more suggestions. I've added about 10 more programs and formatted it better this time around. I have a html version of this already done, so unlike last time, I will be able to make good on my promise to make this into a bit of website.

So post away with programs you have found useful/interesting. I would appreciate if you could keep it in a similar format. Non-commercial programs would be preferred as would lesser known ones (i.e. don't go posting about Photoshop or 3d studio max)

Categories (so far). The XXXXX category is not porn, its just for programs I don't know what to do with yet.

Audio
CD-ripping, music file conversion
Chat
Download accelerators/managers
E-mail
File transfer/sharing
Firewalls
Gaming
Image Editing/Viewing
Internet
Office
Recording
Skinning/Interface
Spyware removal
System tools
Text editing
Video editing
Video playing
3d modelling
XXXXXXXX


AUDIO

Name: Audacity
Description: Record, play, export audio tracks in WAV, AIFF, OGG, MP3, add effects etc
OS: Windows, Linux, Mac
Cost: Free

Name: Fruity loops
Description: Virtual studio type program, create music etc.
OS: Windows
Cost: $49-299 (depending on version), free demo available

Name: Goldwave
Description: Digital audio editor
OS: Windows
Cost: $40 (US)

CD-RIPPING, MUSIC FILE CONVERSION

Name: dBpowerAMP
Description: Rip CDs, convert music files to various formats
OS: Windows, Linux (via Wine)
Cost: free

Name: FreeRIP
Description: Simple to use ripping program that does everything that the average user needs.
OS: Windows
Cost: Free

CHAT

Name: Gaim
Description: Alternative to AIM. Works great and the plugins are very nice.
OS: Windows and Linux
Cost: Free

Name: Trillian
Description: An all-in-one chat program, does AIM, MSN Messenger, Yahoo! Messenger, ICQ, and IRC.
OS: Windows
Cost: None for Basic, $25 for Pro

DOWNLOAD ACCELERATORS/MANAGERS

Name: Flashget
Description: Download accelerator
OS: Windows
Cost: Free

Name: LeechGet
Description: The ultimate download utility.
OS: Windows
Cost: Free

Name: Net transport
Description: Download accelerator (100% spyware free!)
OS: Windows
Cost: free

E-MAIL

Name: Mozilla Thunderbird
Description: Great e-mail client.
OS: Windows/Linux/Mac
Cost: Free

FILE TRANSFER/SHARING
Name: Bit Torrent
Description: Download and send files with this little program. Works like edonkey, and has many places that you can download stuff with it.
OS: Windows/Mac/Linux/
Cost: Free

FIREWALLS

Name:Outpost Firewall
Description: Firewall with attachment, content, advertisement filtering, open port monitor and more.
OS: Windos
Cost: free

Name: ZoneAlarm
Description: A great firewall (software) that enables you to control what comes in and goes out.
OS: Windows
Cost: Free

GAMING

Name: GTKradiant
Size: Depends on what game packs you download
Description: A useful, reliable, editor for JO, JA, Elite Force, Return to Castle Wolf. and other PC games.
OS: Designed for Windows, Linux and Mac
Cost: free

Name: Qtracker
Description: A great alternative to Gamespy that supports JK and MotS.
OS: Windows
Cost: Free

IMAGE EDITING (2D)/VIEWING
Name: IrfanView
Description: image viewer/converter, make screensavers and slideshows from images
OS: Windows, Linux (under Wine)
Cost: free

Name: GIMP
Description: Graphics program similar to photoshop.
OS: Windows, Linux, Mac
Cost: free

INTERNET

Name: Mozilla Firefox
Description: Internet browser.
OS: Windows/Linux/Mac
Cost: Free

Name: Opera
Description: Internet browser.
OS: Windows/Linux
Cost: Free (ad-supported)

Name: Pop-up stopper free edition
Description: Free pop-up stopper
OS: Windows
Cost: free

OFFICE

Name: OpenOffice.org
Description: Fairly fully-featured open source office suite.
OS: Linux, Windows, Solaris
Cost: free

RECORDING

Name: CamStudio
Description: Record on screen activity into an AVI
OS: Windows
Cost: free

Name: FRAPS
Description: make video recording of gameplay
OS: Windows
Cost: free (with restrictions), full version: $US29.95

SKINNING/INTERFACE TOOLS

Name: Objectdock
Description: A snazzy looking program bar
OS: Windows XP/2000
Cost: Free

Name: Wonderful Icon
Description: All purpose wonder utility
OS: Windows
Cost: free

SPYWARE REMOVAL

Name: Adaware
Description: Removes spyware, works best in conjunction with Spybot.
OS: Windows
Cost: free

Name: Hijack This + CW Shredder
Description: Hijack helps you see what, among other things, is running on your computer. Not everything it sees is spyware, but it's great at finding hidden crap. CW helps remove fragments of the henious Cool Web Search spyware.
OS: Windows
Cost: Free

Name: Spybot
Description: Removes spyware, works best in conjunction with Adaware.
OS: Windows
Cost: free

SYSTEM TOOLS

Name: Ace Utilities
Description: Tools like Registry Cleaner, Disk Cleaner, Duplicate File Finder, Internet History Eraser, Startup Manager, etc.
OS: Windows
Cost: Free

Name: Belarc Advisor.
Description: builds a detailed profile of your installed software and
hardware, including Microsoft Hotfixes, and displays the results in
your Web browser.
OS: Any Windows interface. Unsure of Linux compatibility.
Cost: Free.

Name: DCOMbobulator
Description: To verify the effectiveness of Microsoft's DCOM patch, and to shut down DCOM completely.
OS: Windows
Cost: Free

Name: jv16 Power tools (older free version)
Description: Registry cleaner, back up, temporary file removal
OS: Windows
Cost: free

Name: RAM Idle
Description: keeps track of free memory and processor usage. lets you free up any amount of memory you want at a given time and will also do so automatically if you want.
OS: Windows
Cost: free, though there is a pro version for $13.95

Name: TinyResMeter
Description: Small lightweight system monitor
OS: Windows
Cost: free

Name: TweakUI
Description: This program gives you access to system settings that are not exposed in the Windows XP default user interface, including mouse settings, Explorer settings, taskbar settings, and more.
OS: Windows
Cost: Free

TEXT EDITORS

Name: Crimson editor
Description: HTML, /C++, Perl, Java, Matlab and LaTeX source editor.
OS: Windows
Cost: free

Name: SciTE
Description: All purpose text pad. Works with 25+ languages.
OS: Linux, Windows, Mac
Cost: free


Name: Texturizer
Description: Text editor for nearly 30 languages.
OS: Windows<
Cost: free, $19.95 to register


VIDEO EDITING

Name: Videomach
Description: Video editing program, support for AVI, MPEG, FLIC and HAV construction
OS: Windows
Cost: free

Name: Virtual Dub
Description: Video editing program
OS: Windows, Linux (under Wine)
Cost: free

Name: Name: Wax
Description: Video editing program
OS: Windows
Cost: free

VIDEO PLAYING

Name: MPlayer
Description: Plays just about every video file available (makes Cool Matty quiver with excitement at the mere mention of its' name)
OS: Linux
Cost: free

Name: Videolan
Description: Plays many video formats, focus on multimedia streaming
OS: Everything
Cost: free

Name: Xine
Description: Play many video formats, supports streaming.
OS: Linux
Cost: free

ZIPPING

Name: 7-zip
Description: Compression program that supports 7z, ZIP, CAB, RAR, ARJ, GZIP, BZIP2, TAR, CPIO, RPM and DEB
OS: Windows, Linux (CLI under wine only)
Cost: free

3D MODELLING
Name: Blender
Description: 3d modelling program with a animation and raytracing capabilities
OS: Windows, Linux, Mac, FreeBSD
Cost: free

Name: Milkshape 3D
Description: 3d modelling program with animation support for many game model formats.
OS: Windows
Cost: 30 days free, then $25 (US) to register and reactivate saving functions.

Name: POV-RAY
Description: Create raytraced scenes using text language
OS: Windows, Linux, Mac
Cost: free

Name: Terragen
Description: Create photorealistic terrains
OS: Windows, Mac
Cost: free for non-commercial use, $79 (US) for commercial use and removal of image size restriction.

Name: Wings3D
Description: 3d modelling program, no animation capabilities
OS: Windows, Linux, Mac
Cost: free


XXXXXXXX

Name: Wink
Description: Create flash tutorials for computer programs
OS: Windows
Cost: free

Name: Atmosphere Lite
Description: Listen to nature sounds while you sleep. Even has a built-in alarm clock. There are tons of various sound presets.
OS: Windows
Cost: Free

Name: Flash Toolset
Description: Useful for decompiling .fla files.
OS: Windows
Cost: V1.0: free v2.0: $

Name: KeyNote
Description: Notebook tool for neat organization freaks.
OS: Windows
Cost: free

Thanks to the people who contributed to the original thread (in order of appearance): Jin, Molgrew, MentatMM, Echoman, Crimson, Hebedee, Noble Outlaw, Lord Kuat, DrkJedi82, Ric_Olie, Mystic0, Fastgamerr, fourwood, Freyr, SithNazgul

Nice list! You got it all pretty much.

AIM:
Middle Man
DeadAim
Two cool AIM extension things. Tabbed Chatting, Cloning Aim, Invisibility, Chat logging, and tons of other stuff.

Image editing:
OpenCanvas
Cool program for line drawing.

Project Dogwaffle deserves a mention in image editing as well. Very useful for drawing things if you have a tablet. Old free version used to support ~60 image formats. New one only supports targas and bitmaps, which is a bit of a downer.

ConText
Great text editor with many useful tools and highlighters for many programming languages and even more for download.

In addition to Blender, I *MUST* recommend this script:
Name: MakeHuman.
Desc: Automatically generate a human model in Blender and edit nearly all human features (yes, including genitals). Script is not completed, but is fun to play with. You cannot yet save models (or at least, I haven't found out how to, and no tutorial is yet available.)
OS: Any that support Blender.
Cost: Free

CD Burning/Ripping:
Name: CD Burner XP Pro
Desc: Burn Audio or Data CDs, Rip Audio CDs, or burn CDs from ISOs. Also converts BIN to ISO (although a bit buggy still). Frequent updates available.
OS: Windows 98/2000/ME/XP
Cost: Free

AntiVirus:
Name: Avast! Antivirus
Desc: Virus protection software, database is updated constantly and automatically downloads to your pc. The program is very quick in recognizing malicious code. It's even picked up before a program completes downloading and is executed. Also on their site is Avast! Virus Cleaner.
OS: Windows/Linux
Cost: Free, but you must register (also free)

foobar, but going to work so don't have time to dig about for info.

it plays, it converts, it's lightweight, it's free, it rocks.

EDIT :: Cheers to Molgrew for the linky, I was about to put it back in but I've been usurped!

CD-RIPPING, MUSIC FILE CONVERSION

Name: CDex
Description: Rip and convert CDs to many file formats.
OS: Windows
Cost: free

XXXXXXXX

Name: Agent Ransack
Description: Find files and information on your HD fast and efficiently. Regular expressions with complex rule based searches, immediate contents results view.
OS: Windows
Cost: free

Name: Picophone
Description: PicoPhone is a simple and really light weight Internet phone application with chat.
OS: Windows
Cost: free

Audio

Name: foobar2000
Description: basic features include ReplayGain support, low memory footprint and native support for several popular audio formats, Masstagger, diskwriter etc.
OS: Windows
Cost: free

Name: Burrrn
Description: Burrrn is a little tool for burrrning audio CDs with CD-Text from various audio files. Supported formats are: wav, mp3, mpc, ogg, aac, mp4, ape, flac, ofr, wv, tta, m3u, pls and fpl playlists and cue sheets
OS: Windows
Cost: free

CD ripping

Name: EAC
Description: Rip highly securely and convert CDs to many file formats
OS: Windows
Cost: free

Zipping

Name: TUGZip
Description: provides support for a wide range of compressed, encoded and disc-image files, as well as very powerful features; all through an easy to use application interface and Windows Explorer integration
Cost: free

*quivers*

Anyway

I don't have time to make links for these yet, but if you wait till later I'll get them:


Video Editing: Adobe Premiere
Description: Awesome video editing program with lots and lots of features, and easy to use interface, and a 30 day demo.
Price: (More than $200 I think, I'll check later)

Cinerella:
Description: Video editing program for Linux. While not as good as Adobe Premiere, it gets the job done, and for a good price.
Price: Free

File Sharing:
BitComet. Easily the best BT client.

File Sharing:
BitTornado

Advantages: Very similar to the BitTorrent client with added features. Control upload speed, how many threads, and port range.

Disadvantages: Only minutely faster than original BitTorrent client

Zipping:
UHARC

Advantages: Let's just say I've seen it zip 1.5 gigs into 300 megabytes. It's that good.

Disadvantages: Takes forever.

Here's a good question for ya'll:

Anyone know of a good linux bittorrent program that runs IN CONSOLE? Note that last part is very important. I have a server system with no head and of course no X system. But I want to use torrents on it, and atm the only program I have doesn't seem to work right. (ConsoleTorrent)

BitTorrent.

It has a commandline version.

Eh? It does?

Yes, and if you have php installed you can monitor it with a script called torrentflux.

I haven't really used torrents since suprnova went down.

plus, torrents are quite slow.

You obviously used suprnova for too long.

CoolMatty--yes, you just need to have python installed.

"btdownloadheadless"