Gaming build <700

This gonna be my first gaming build and i would appreciate if someone could give me tips or suggestions because i don't know very much except putting it together. So i am planning on running BF3 and games like that so i am sure its hard on a the components. If you have any better components that i should add that would be nice just try to keep me around 700 bucks.

CPU AMD FX-6100 3.30 GHz Six Core AM3+

Motherboard GIGABYTE GA-990FXA-UD3 AMD 900 Series Cpu/MB bundle for $360 and come with BF3

Graphics Card no clue yet this is where i need help

DDR Ram another big ?

PSU DiabloTek PHD350 350-Watt Power Supply 20 bucks i dont know if this an ok spot to bottle neck

HDD WD Caviar Blue WD7500AALX 3.5" Hard Drive - 750GB, SATA 6 Gb/s, 7200 RPM, 32MB, 3.5" $109

OP system win7
I have the drive keyboard and mouse please help me out any help is nice. Tell me if i forgot anything too.
Thanks!