Since having ram issues way back in the olden days, I have been pretty religious about buying ram from the motherboard's QVL.
Ram should be bought in "kits" that is, all at once in a package, rather than individual sticks (even from the same manufacturer with same timings and all).
I would purchase ram from one of these companies as a personal preference; AData, Kingston, Corsair, or GSkill.
The Corsair Vengeance line and GSkill Ripjaws line of ram are both popular
also stay out of the value line of products. your better off paying few dollars more for vendor that uses new tested ram then 2 and 3 level ram markets. also with ram look at the height of the heat spreaders. some of them are so tall they dont fit under some heat sinks. also with heat sinks make sure to buy one that wont block two of the ram slots on you.