[Ultimatum]

Intel Core 2 Quad Q6600 @ 2.4Ghz.

It's a decent CPU, and was was regarded very highly when I bought it, about 5 years ago (approximately). Not sure about temperatures, but it can run most new games on medium settings pretty well. Planning on buying a i7-3770K for my next build.

That's alright, I recommend you not to get the i7 though, simply because it is not worth the money for it. If you are a familiar over-clocker then you should have on problems over-clocking an i5 over top of the i7. However, it's all up to personal preference.

Also make sure that if you do over-clock, get a CoolerMaster 212 EVO CPU Cooler. It's cheap and the best. I managed to get 60 degrees while using Prime95.

There seems to only be a $100 difference between the two. I want my computer to be able to play the best games for the next 5 years. Wouldn't the extra hundred be worth it?

Because the 100 dollar difference isn't actually worth the 100 dollar difference. Do you know how to over-clock? I played new games on this new build with this CPU on ultra settings with a minimum of 40 FPS. Most games at 60+. Starcraft II at 195 FPS. i5 is really enough for gaming. Though your GPU is also important. It all depends on budget but my Gigabyte is only a NVIDIA GTX 660 2GB and it ran more than one game smoothly.