Suggestions: [url]www.sysinternals.com[/url] makes useful little tools.
There are two separate .NET frameworks: 1.1 and 2.0 (and that's if you don't count 3.0 beta)
Latest DirectX. Don't forget that. Download the web setup version so you'll get the latest components (dxwebsetup.exe).
Winamp, uTorrent, Google Desktop Search (unless you know where all your files are at all times), Google Talk...
I use Trillian for chat, but since it costs $$$ for the version that's worth using, GAIM or Miranda IM should work in a pinch too.
Don't forget mIRC for IRC.
Also this site
http://www.crystalxp.net/ links to a bunch of cool freeware (some trialware) tweaking apps for Windows. On that note, don't forget the PowerToys for XP from Microsoft either.
Others in the same vein of mini-tray-apps not showcased there are "D-Color" which allows you to show the desktop in Tiles view, "allSnap" which adds Winamp's, etc, window snapping ability to all apps, "Glass2k" which allows you to make any window partially transparent (although I've had problems with Windows occasionally not updating), "TaskSwitch XP" which is the best Alt+Tab app around which also has a bonus feature allowing you to minimize any app to the tray, "WinSnap" which is the best screenshot app around (coincidentally both made by the same authors), and "Archive Folder", which allows you to browse RAR, ISO, etc archives in Windows Explorer in the same way you can open ZIPs in a default XP install.
Find and apply "Command Prompt Here" and "Explore From Here" registry patches too.
Fooling around with "Transformation Packs" is fun too, although you have to be careful so as to not break Windows (just be sure not to install/uninstall Microsoft stuff that requires a restart, especially IE things or Windows Update things, in the same session as you install/modify/uninstall a transformation pack). There's one for Vista (which I use), one for an OSX look (FlyAKiteOSX, I used it for a bit, it's good :)) and that crystalxp site has a good looking one too. They typically patch system files for icons, bitmaps, animations, etc, patch your uxtheme.dll to allow for non-Microsoft themes and visual styles, and optionally install extra tray apps like the ones I listed above to make Windows act more like the target OS, as well as skins for some popular third-party apps.
Questions:
1) Short answer: Comply. Long answer: It's best to comply, but if you must, there are settings buried in the control panel app that tell it to STFU.
2) Steam will run without a proper install (I like to say all well-written programs do), but you need to delete or rename ClientRegistry.blob, because it contains absolute paths to all Steam resources, so if they change location or drive letter, Steam will think you have no games downloaded. Deleting it forces Steam to recalculate paths.
3) %APPDATA%\Mozilla\Firefox\Profiles\<random>.default\bookmarks.html holds Firefox's bookmarks. Overwrite one with the other. Sticking %APPDATA% in Start | Run will take you to the relative folder for your current account.
Preferences:
1) Short Answer: None. Long Answer: It's a well-spread myth that disabling services will increase speed. Usually, they only use resources when they are needed. If you are concerned about memory, keep in mind Windows will simply swap them to disk until they are needed, so there's really no performance hit while you're playing games or whatever. Don't be afraid of numbers in Task Manager.
That said, if you want to disable services just because you'll never use them... run services.msc from Start | Run and you'll get the full list. You can use the names and descriptions to figure out what they are, but unless you understand what it is, leave it alone. The startup types can be set to allow or disallow a service to start automatically when the computer starts: Disabled - Won't start and can't be started at all until this setting is changed. Manual - Will start only when explicitly asked to. Automatic - Starts as Windows' GUI does. Boot (not configurable though the GUI) - Starts as the computer boots.
Messenger service is one of the few you might need to disable since, on certain network configurations (ie bad ones), you can get popups with it over the internet. "Server" powers Microsoft File and Printer Sharing, and can be disabled if you wish. Turning off "Themes" reverts Windows to drawing everything in classic mode.
"Wireless Zero Configuration" (XPSP2) only has value if you use wireless networking.
2) Short Answer: You don't. Long Answer: You would need a program to completely replace the taskbar, such as ObjectBar (
http://www.stardock.com/products/objectbar/) or Litestep or something.
3) Yes, right click taskbar, click properties, uncheck "Hide inactive icons".
4) TweakUI XP from Microsoft will do this, under the option "Autologin". Google for it.