For what its worth, I put a Crucial MX100 256gb in my Asus 1215n netbook and its decent. I almost bought another MX100 for my main rig. Samsung seems somewhat expensive. Best of luck.
I would say get the high capacity sticks so that you can expand later down the road. I don't know about the technicalities of quad chanel over dual chanel. Get fastest sticks possible....quad channel might be faster....profit. Good luck.