well none of these motherboards are good overclocker so I am assuming you don't want to overclock. In that case, you may consider i7 2600 because it has hyperthreading. 3570k on the other hand is a good overclocker but your b75mobo won't support it much. So its a waste.
My advice, either get the 2600
or the 3570k with a z77 motherboard if you want to overclock your cpu.
either cpu will dominate in gaming and other tasks so you will be fine either way. ht adds 25% performance in theory where IB is roughly 10% better than SB. Get the deal that saves you more money.
Goodluck!