If you want to use a computer for gaming, AMD is for you. That processor, mobo, and graphics card is a good choice. Generic ram isnt the best, try to get some brand name ram like Kingston Valueram. Also, generic power supplys can cause damage and unstability over long periods of time. I suggest a Antec case because they bundle with good Antec power supplys.
Core 2 Duo E6400, DFI Infinity 975X/G, 2x 512mb DDR2 667mhz, Albatron 7900gt, WD 200gb SATA, Samsung DVD-RW, Silverstone ST-50EF 500w PSU.