Here at SJSU, we've used the "Morpheus" rig a lot which is pretty good, but has a lot of trouble in the shoulder area. One of the main problems is that there are lots of different controls, and also that the model easily gets distorted and twisted there in the upper arm. Try to keep the shoulders simple, with just two or so controls, but still very expressive because we use them a lot.
It's nice when the hands have controls that move multiple fingers, like to cup the hand or flex it, bring the fingers together, or separate them. It can be annoying having to select each joint for every finger just to mold the hand once, though the individual joint controls should also be included, of course.
Have both IK and FK controls for the hands, feet, and head...
It's fun to have controls on the foot for ball-roll, heel roll, toe pivot, heel pivot type movements...
That's all I can think of just now! Maybe a control in his hat or even his stomach so we can have nice overlapping action.
