ill give you a list of parts i'd use:
AMD Phenom II X4 955 Black Edition $120
BIOSTAR A870 AM3 $60
radeon 6850 or nvidia GTX 460 depending on what games your gonna run $150
ADATA XPG Gaming Series 4GB (2 x 2GB) 240-Pin DDR3 SDRAM DDR3 1600 $30
a western digital calvalier black whatever size you want (750g $64)
RAIDMAX HYBRID 2 RX-730SS 730W $65
LITE-ON DVD Burner $18
ZALMAN CNPS 9500 AM2 $45 (if you want to overclock...which you do)
Arctic Silver MTX-2.5G Matrix Thixotropic Premium Thermal Compound $5
and a case of your choice! i suggest the Rosewill CHALLENGER for $50
Thats ~$600 for a computer that will play any game you want at decent to high settings.
i have two questions for you though. what resolution is the screan you will be playing on? and what games do you think you will be playing?
~dont forget you need to buy an OS!
thanks man! i want to play things like americas army 3 and batlefiled 2 at least if not bf 3. And an OS wont be a problem ive got connections(;