2500k or 3570k?

I know Ivy has a 10-15% performance increase clock for clock over Sandy but considering the amount of heat Ivy puts out (OC'ed), I'm not too sure on what I should get.

I'll roll with the stock cooler for a while, untill I can get some money for a Dark Rock Pro Advanced 2.

I just want to know, what CPU will preform better/overclock higher?

I will be getting the Gigabyte GA-Z77X-UD3H so the board should be able to handle better overclocks.

Definitely the 3570k. You should be able to OC to 4.5Ghz with much lower volts when compared to the 2500k, but you still need to take into account the silicone lottery

They're both pretty much the same. You'll be able to get 4.5/4.6GHz out the Ivy, and anywhere from 4.7-5GHz on the Sandy. Will be pretty much the same performance. I'd roll with the Ivy, just because the newer motherboards shall be better at integrating themselves with the chip. Ivy also has a superior memory controller, if you ever want to roll with some high-speed (and utterly useless) memory.

What a noob... I can't believe I forgot about native USB 3.0 and PCI-E 3.0

Thanks for your help again Josh =)