I am currently stuck between these 2 processors. I know they wouldn't make that much difference for gaming, but what is better for other non-gaming tasks? I will over-clock the i5-3570k to 4.2 GHZ but how far could I overclock the i7-2600k? Power isn't an issue, but I have a 612pwm as a cpu cooler so heat is the issue here. The i7 seems like the better choice here, but I will get the i5 if it will be better when overclocked.
Here is my build if you need that info: http://pcpartpicker.com/p/cyXX
It kind of depends on what "non-gaming tasks" you are talking about. The main difference is that the i7 has hyperthreading, but if the applications you are going to be using don't use hyperthreading then you are better off saving a few bucks and going with the i5. The i5 will be slightly faster because of it being Ivy Bridge, but you won't notice it unless you're benchmarking. Also, I have read that the Ivy Bridge get hot when overclocked past a certain point so if heat is a huge problem you might be better off looking at an i5-2500K.