Newer games support more than two cores ... not all ... but as time goes by they will.
The E8500 is a good choice if your happy to not overclock, and it will give you good all round performance, as you have 2 cores flying at 3.16.
If your going to overclock, then look at a comparable priced quad, preferably one with the 12Mb cache ... as upping the clock on it will return a much more predictable performance boost for you.
Hope this helps.