In the long run the Core i5 will be better for gaming especially if it is a 2nd generation Sandy Bridge CPU like the i5-2400 or i5-2500.
A lowly dual core Core i3-2100 (the slowest Core i3 there is) can beat or equal a quad core Phenom II X4 980 BE in all the various game benchmarks comparison I have seen; About 7 or 8 games. The only game the Core i3-2100 lost to the Phenom II X4 980 BE was Mafia II. I forgot what video card was used, but the Core i3-2100 got 89.0 frames per second vs. 89.9 frames per second for the Phenom II X4 980 BE.
There are different ways of looking at performance between sandybridge and bulldozer, core to core sandybridge beats the FX series. While in multithreaded the FX-8150 and the core i5 2500k exchange blows.
Internet Cable please try to provide some backing with your claims rather then just stating preferences.
Such to buy a phenom would be pointless and this stage with the FX series being released and sandybridge being affordable. Look between the two and find something in your price range.
OK, here's the thing. i am defiantly going with am3+. which would be better for my money? i can get a phenom quad core 3.4 GHz for $119, or the fx-4100for $129 (3.6 GHZ, quad core). could the fx be better for the extra $10? or would the fx-6100 be better in the long run ($179)?