Well for starters do you already have the motherboard? I noticed you have the i7-875 listed for a 1156, while the other two are 1366.
I would probably go with the 1156, seeing as how it's an unlocked multiplier and 95w. I could OC that easily past 3.0GHz on air. (better than the 3.06Ghz on the i7 =P).
Buut - if you want cheaper: maybe a i7-870
works better? It's $289 @ 2.93Ghz, or the i7-930
for $284 @ 2.8Ghz - and with a good enough Cooler
it should easily reach 3.0GHz and up with either one. x)