I've gone with a pair of Fox Titan Sport elbow pads. They seem simple, not too big. Got em from Winstanley BMX (free delivery, which gets my business every time!).
Being new to this (and indeed anything that needs elbow pads), I probably won't be able to give a balanced review of them, but if (I should probably say when) I fall on them, I'll tell you what happens to my elbow!