ct1615 :
at stock speeds
http://anandtech.com/bench/Product/88?vs=109
Well I noticed a lot of people are choosing which procesor to buy due to that bench graph (especially between i5 750 and x4 955).
Anand took those results from there reviews and if you look at the 955 review, he used an AM2+ motherboard with DDR2 ram. If he would used AM3 with DDR3 ram, results would be much better. So for gaming theres almost no difference between the two, excluded few games which run better with intel (Far Cry 2 for example).
As already said only thing is future proof, but if you always buy a new motherboard then the i5 is a great deal.