AMD was more cost effective at the low end of the market up until very recently.

A good summary of gaming cpus can be had here:
http://www.tomshardware.com/reviews/…lock,3106.html

I recommend just reading through it and you will see pretty much even entry level cpus are now fine for even the most demanding games these days. If you have money to burn though I would go for the 2500k.

Every month prior to feb 2012 AMD took out the bottom 2-3 slots.