core i5 6600 or i5 6600k?

Solution
That depends on whether you want to overclock or not, or if the extra 200mhz on the base clock is worth the extra 25 bucks to your or not. I think it's worth it, but you may not. Both are good enough for almost anything you want to do, so in reality, if you have no plans to overclock and aren't specifically concerned with the stock clock speed, the locked chip should be fine. Otherwise, go with the K SKU chip.

That depends on whether you want to overclock or not, or if the extra 200mhz on the base clock is worth the extra 25 bucks to your or not. I think it's worth it, but you may not. Both are good enough for almost anything you want to do, so in reality, if you have no plans to overclock and aren't specifically concerned with the stock clock speed, the locked chip should be fine. Otherwise, go with the K SKU chip.

 
Solution
Very true man, I personally think getting the overclockable one is more value when looking at it in a future proof point of view. If your looking at multi gpu configs later on then being able to overclock is a nice thing to have. But for good quality gaming for many future titles then the non-K SKU will be fine!
 


Doesn't the 6600k also laking the CPU HSF with it? If so, the CPU HSF would need to be purchased additionally, thus costing an additional $20-40 depending on which cooler you select.
Obviously if you already have purchased an aftermarket CPU HSF or water cooling option, you won't need to worry about the additional cost.
Personally I would go with the i5 6500 and save about $20 over the 6600 and use the extra $ saved on upgrading other parts of the build, if they haven't been already purchased. That is just my opinion, so take that into consideration.
 
And if you go with the non-K CPU, you won't need a z-series motherboard, which means you can save another $25-50 on the motherboard price by getting an h110/170 one instead, $30-100 on aftermarket cooling by using the stock HSF, and yet another few bucks on memory by going with plain 2133MT/s DDR4 instead of 2400+MT/s.

All-inclusive, going with non-K will save you $75-125.