I don't really have one, but if I had to pick one I would probably go with one of the Muppets. They are pretty cool and seem to have a fair amount of fun.
Which one is a harder question. Kermit is okay, but he get stressed out a lot and I am pretty sure he will snap someday.
Piggy is too full of herself, that really isn't me.
Sam the Eagle is TOO uptight. He needs to relax a bit before he blows a gasket.
I like Animal, but he can get a bit too carried away and crazy. Not to say I don't get crazy from time to time, but not quite to that extent.
Fozzy is a possibility as I do tend to come up with bad jokes and try to have a good time when I can.
Perhaps the best would actually be an amalgam of several of them. A bit of Kermit, a bit of Fozzy, a bit of Animal, and perhaps a bit of Bunsen Honeydew. That seems about right.