Intel Core 2 Is Good For pretty much all The games out now, get Like a ati hd 5770 or go A little higher to the 6xxx series
Newegg.com - 5770
i have a ati hd 4650 and a pentium 4 single core and i can Play modern warfare 2 and like 25 - 50fps, if i had a dual core i Could get a lot more