People, he said he want's the BEST cpu and mobo for $600.
That would not be a i5-2500K, it would be a i7-2600K and P67. You could do both of those for less than $500. The mobo you get depends on whether you want xfire or sli.
The i7 is not going to be faster at gaming than the i5, but it'll be a lot faster at a lot of other things and MUCH more future proof with it's 4 extra virtual cores (HT)