I'm buying a new computer, but I've basically been out of the know since I last upgraded the computer, which was somewhere around 2003. So I'm quite lost when it comes to deciding on what to get.

I've done some reading and selected these components, and I have some questions for some. FYI this is intended as a gaming rig.

Intel Core2 Duo E6850
GeForce 8800GTX - Anything I should know about this card? I've read that the performance increase between this card and the GTX Ultra doesn't really justify the extra cost, but would it be worth it in the long run? Also, is there any difference between manufactures? I was looking at an XFX but an Asus is considerably cheaper, but I don't know what the difference is here.
4GB Kingston 5300 (2x2GB) - Kingston RAM is still good, right? Also, is 4GB enough?
As for the motherboard, I have no idea. I was looking at an Asus Striker Extreme, but it's got a lot of bells and whistles that I don't think I'd have any use for. I'd just like a high quality board for the CPU and video card I want. Suggestions would be awesome.
For audio I was just going to stick with onboard sound, but that would depend on what motherboard I go for. I have Logitech X-530 speakers if that makes any difference.
Power supply I'm looking at is a Seasonic M12 700W. I don't know if that's of any consequence or not but there you go.
And for Windows Vista, I was thinking Home Premium would be sufficient, yeah?

Cheers in advance.

I'd stick with 2gb of RAM. Honestly, any more may be overkill. If you find it's not enough you can always get more.
I'd suggest DFI for the motherboard personally--great gaming boards. Tech support leaves a bit to be desired but they're generally fairly good.
Other than that, looks good.

If you're spending this much on a box, and you have halfway decent speakers, at least get a 20 or 30 dollar soundcard. You'll be much happier, and even a kind of crappy one is usually better than onboard.

As far as soundcards go, you can get the Audigy 2 for fairly cheap and it's a DECENT card. I'm sure some (such as Emon) will have better suggestions.

I'd go X-Fi if I could and I were you, but that's just me. You may not be too worried about how your **** sounds.

I'm by no means an audiophile but if there's some noticable difference between onboard and a dedicated card then I would want to go with the better option. All I really want out of it is 5.1 sound.

The supplier I'm buying through only stocks Asus and Gigabyte boards, so I don't know what to do about that.

I'd actually avoid the nforce chipset this time around. I've heard a lot of complaints about them.

For Intel? I've heard great things about them.

Yeah I just did a little reading on the 680i chipset and it sounded pretty good. What are the complaints?