I don't really have a favorite - I've had Hopper in ACCF and Grizzly in ACNL, they both look okay but since they're cranky I love them too much to even consider letting them move out. I get ridiculously attached to the cranky villagers, and I only ever have one of them, which certainly only adds to that.
Lobo :3 may be cranky but he is so sweet to me (when you get stung by bees and talk to a cranky villager they will say "its a shame to see such a pretty face end up like that" around something like that)