However, you should simply go to the website for the motherboard you're looking at. It will display the supported memory speeds.
I picked a random Z77 motherboard from Asrock and it supports up to 2800MHz DDR3:http://www.asrock.com/mb/overview.asp?Model=Z77%20Pro3&cat=Specifications
(While the CPU has a memory controller, I think many motherboards do as well and the motherboard chooses the best controller for the job, although I don't know how it decides. All the motherboards mention the top RAM speeds with the abbreviation "overclock" beside it so I'm unclear exactly how that works.)
*I believe Windows 7 Premium 64-bit only supports up to 16GB. You may wish to use 32GB if you do video editing, though you wouldn't need that much for photo editing. But if you do get 32GB go with Windows 7 Pro. You might want to get Windows 8 Pro 64-bit actually which I think comes out in June; I may not like the interface but there are quite a lot of subtle tweaks with memory, security, file system etc.
**Quicker timings are sometimes better than faster RAM. I've actually seen 1866MHz RAM that benchmarked SLOWER than 1600MHz RAM that had good timings (7-8-7-24). I saw a detailed test very recently with the fastest CPU that basically shows no benefit for any tasks above the 1600MHz 7-8-7-24 DDR3 RAM.