[CaptainHaplo]

Onelife - seriously reconsider the 450W ps...

The 4850x2 alone requires a 650W ps. You try hooking it to a 450, your going to have problems.

With the rig your looking at - a 750 or 850 Watt is probably a better long term option.

DO NOT SKIMP ON THE PS! I suggest something like Corsair or other high end, quality PS.

I just picked up a 750W Corsair for $120. Can't beat that when it has a 5 year warranty.

Processor questions have already been addressed. As for vid cards, I have used both Nvidia and ATI, have been on ATI for most of the recent years, but went ahead and got a GTX260 OC'd out of the box by BFG. Lifetime warranty - $200. So far, I haven't been able to force ANYTHING I playunder 60fps. (But dang that thing was HUGE!)

For Crossfire/SLI - you have to have 2 pci-e X16 slots - and usually you have to use the same family of cards... Like 2 GT9800's - but not a 9800 and an 8800. Going with an X2 style board is fine as long as you make sure your Mainboard has the room for it without losing additional slots because they are covered.

More memory is always good. If you choose 32 bit OS though, don't get over 4. It can't address it.

No reason not to go 64 bit UNLESS you run really old stuff. Then, you have dosbox. 7 is definitely the way to go regardless. Its what Vista should have been years ago.