A 2500k could handle 2 670s if you want, so no problems with bottlenecking
An ASUS Pro Z77 board is great. The ASRock and Gigabyte offering are worth a look to. There are quite a few to choose from. I will not single one out as I do not know your particular needs i.e wi-fi? Future SLI? heavy OC? lots of SATA?
Decide on what your needs are then find a board which matches it for a good price.