If it makes me laugh out loud, it gets lurve. If it makes me think, it gets lurve, especially if it teaches me something. If it says what I would say, only better, it gets lurve. Other than that, not so much. And often, I get so into answering, that I forget to show others that I appreciate what they said. Sigh.
It disturbs me that moderators can see who hands out lurve at what rate. I think I reserve it for really high quality (i.e., truly great answers).