I just built a similar machine to that, but with a GeForce 9800 card. It plays StarCraft 2 on the highest settings.

My only suggestion is not to cheap out on the PSU. Linkworld is garbage, I've been using the OCZ brand PSU's and haven't had an issue. Also, get RAM that matches the specs of the AM3 board and not some PC100 crap you have "laying around." I would get 2x 2GB sticks of OCZ, I think they are on sale.