I was gonna suggest the 8800gts, but i thought u were on a budget.
that msi card is great...but for the games u mentione....the 9600gt will do perfect.
a 9600gt win play those games like candy.
get teh q6600 with the ds3l...
u can oc the q6600 to 3ghz like a piece of candy and ure set man
your pc will be able to handle a lot of games and u will be really happy compared to the dell system.