What CPU should i get?

Eximo

Titan
Ambassador
Well if you want to overclock a Z77 board and the i5-3570k can do it.

Z97 board would go with an i5-4690k for overclocking. If you are talking about a regular i5-4690 you could save a little by getting an H97 board instead, and you wouldn't need the CPU cooler.

Not much sense in buying a Z77 platform unless you are really scraping by on budget.