loops :
Take the part picker builds with a grain of salt. They tend to have you run around to vendors and dont show in-store price vs on-line price very well. Given the games you plan on playing the build above is just fine. I'd have you look at the build below as well. It comes with a top end card, 3 free games, and will let you max out AA.
ALL FROM NEWEGG:
1 ASUS DRW-24B1ST/BLK/B/AS Black SATA 24X DVD Burner - Bulk - OEM
$19.99
1 COOLER MASTER HAF 912 RC-912-KKN1 Black SECC/ ABS Plastic ATX Mid Tower Computer Case
$59.99
1 CORSAIR Builder Series CX600 600W ATX12V v2.3 80 PLUS BRONZE Certified Active PFC Power Supply
($20.00 Mail-in Rebate Card)
$69.99
1 ASRock Z77 Extreme3 LGA 1155 Intel Z77 HDMI SATA 6Gb/s USB 3.0 ATX Intel Motherboard
$114.99
1 COOLER MASTER Hyper 212 EVO RR-212E-20PK-R2 Continuous Direct Contact 120mm Sleeve CPU Cooler
27.99
1 GIGABYTE GV-R797OC-3GD Radeon HD 7970 3GB 384-bit GDDR5 PCI Express 3.0 x16 HDCP Ready CrossFireX Support Video Card
399.99
1 FREE: AMD Gift FARCRY3 Blood Dragon CRYSIS3 BIOSHOCK (-$119.99 Saving)
Combo:
1 Intel Core i5-3570K Ivy Bridge 3.4GHz (3.8GHz Turbo) LGA 1155 77W Quad-Core Desktop Processor Intel HD Graphics 4000
1 G.SKILL Ripjaws Series 8GB (2 x 4GB) 240-Pin DDR3 SDRAM DDR3 1600 (PC3 12800) Desktop Memory Model F3-12800CL9D-8GBRL
$272.98
Subtotal: $965.92
1>500R is way better than HAF 912 plus its on sale.
2>HX650 is much better than the CX series 600 Watt PSU, you might be doing SLI in the future. There will be no need to replace the PSU.
3>ASrock Extreme 4 is just a few bucks more and will fit in his budget plus its better too.
4>There are some deals on certain GPU, you could have a look on them on
Newegg. And yeah you can buy the Gigabyte HD 7970 if you like.