When it comes to picking RAM, a lot of it is preference, and then the rest is what the board can handle. Your board can handle up to 1600mhz without overclocking, so if your not going to o/c, there isn't any reason to buy any higher than that. If you don't mind o/cing, then you can go up to 2800mhz(if you have a new 22nm CPU).
As I said before, ram is mainly preference, so you just have to find a brand you like first. Personally I like Corsair. Here is a couple links to some nice RAM
Corsair XMS3 Desktop Memory Kit - 8GB (2x 4GB) - $42 http://www.tigerdirect.com/applications/SearchTools/item-details.asp?EdpNo=1124812&CatId=4534
Corsair Vengeance CMZ8GX3M1A1600C9 8G $45http://www.tigerdirect.com/applications/SearchTools/item-details.asp?EdpNo=2952326&CatId=4534