$1200 is the same amount of money I spent on my system.
If you are getting a single core processor, then the FX-series is the way to go, FX-53 is very good but it has overheating problems with stock heatsink even at normal clock speed. (650+new heatsink) If you are going to get a lower end proccessor then you might want to use the dual-core ones, you can get a decent one for around 500$.
DFI LANPARTY nF4 SLI-DR ATX AMD Motherboard (180)
Ultra/Cooler Master Case(70+PSU *optional*)
Nvidia 7800GTX (I know you can get those for around 450 dollars if you look around)
WD 200GB HD 80$ with Rebate
Since most of the new games do not require a CD to Play or has most files already isntalled to your computer, an old CD-Rom would be a better choice than a new one.
Ok I know that is over $1200 but the few extra bucks will be worth it, you don't wnat ot regret spending 100 dollars less for your video card realizing that if you ran SLi you'd probably need two new cards anyways because your current one sucks.
G. Skill 4GB(2x2GB) DDR800
eVGA 8800GTS 320MB
super pi: 1m=20s