My computer has been running bad lately. I got it 2 years ago its a dell inspiron 530-s and put a new radeon x1300 in it. The problem is I can't run newer games with this video card and i can't upgrade anymore because of my slim case so i decided to just build my own computer. I had some help with a couple of things but check it out.
Well I personally do more on my PC than just game. That and since the i5-750 is cooler and uses less power, is why I went that route.
Don't buy expecting to save money on your power bill though. It comes out to ~$10 a year for a 24/7 load system (which never happens).
For a $95 price difference in a gaming only rig I'd say go Phenom II. That $95 is enough for a 5850-5870 upgrade, which is a nice 11%-16% FPS increase, much more than the processor difference would be.