Assuming you already have the i7-2600K, I'd go for a mobo with a Z77 chipset for overclocking potential. Something like a second hand Gigabyte GA-Z77-D3H.
The number of controllers: 1
Memory channels (per controller): 2
Memory channels (total): 2
Supported memory: DDR3-1066, DDR3-1333
Buy the board first, then check manufacturer's QVL (Qualified Vendor List) for recommended RAM. It probably doesn't matter if the RAM isn't on the list. Just make sure it's DDR3. Tighter timings (lower latency) are better.