It totally depends on what the top is looking for, really. It's just like asking, "What's the perfect bj?" Different people like different things. I had one friend that wanted to just lay there, and have me do all the work, basically, so he could claim (justify in his head) that he didn't "do anything". Another buddy of mine told me, "No, don't fuck back. I just wanna see your hands grabbing the mattress, and hear you whimpering into the pillow."
Both, afterward, told me how good it was.
Um, ok... But it just goes to show that it totally depends.