I'll kick off. Mine is - as my avatar implies - Sheogorath. His entire being sparkles originality, from his colorful outfit to his quotes(and I'm not just talking about the 'cheese' line either.)
A close second is Baurus. Not much special about his personality or character, but my characters usually have a sense of loyalty towards him. They befriend him most of the time and he seems like a really relaxed, cool, loyal, brave and honest man.
What about you guys?