LambOfGod - He said he wanted a gaming pc
For the purposes of this post, I'm using newegg.com, but you might want to check around on some other sites.
Intel Core2Duo E6600
Everyone says this baby is awesome, and is highly overclockable.
Motherboard about $150
I don't think I know enough about motherboards to give you a good recommendation, but it has to be socket 775. I'd recommend DDR2 RAM compatibility, because that is going to be the new standard in a few months. Also IMO Asus makes excellent mobos
Graphics Card $319
There's currently a sweet deal on Newegg for the Geforce 7950GT which is basically the fastest graphics card out currently without linking 2 together. For gaming, you really do want to go all out on the graphics card.
2 GB of Corsair DDR2 667. You can't really go wrong with Corsair.
Power Supply about $75
It's really your preference, get one with at least 550 watts. Antec makes very nice ones.
Hard Drive about $100
It's really your preference here, the Western Digital Raptor is very fast, but is only 74 GB and is very expensive. I'd just get 1 250GB Hard drive for storage, but if you want you can by both.
You also have to buy a few more things:
network card? (if not integrated to the mobo)
We went a little over the budget, but this is a lightning quick PC. I assumed you didn't need a monitor, but if you do, get at least a 19" witha response time less than 16ms. If you need to make it cost less, get a different graphics card. I'd recommend this: