In looking over the answers, it's heartening to see how many favorite characters are from spec fic. True, a lot of them are from movies or TV (although with LoTR and Harry Potter characters, you can't tell if the poster is referring to the books or the movies), but still there are a lot from books, too —Anne Rice novels, Twilight series, and even Jasper Fforde. I was also pleased to see someone had listed Dickon, from The Secret Garden, one of my all time favorite books, as a favorite. The book isn't spec fic, strictly speaking, unless you count the hints of Colin's mother's ghost calling out to his father in his sleep, but I love it.
Very few people bothered listing characters they didn't like, and no one mentioned my "Most annoying fictional character" . . . Othello. What an idiot! I hate it when smart, brave people allow themselves to be mislead into doing something incredibly stupid.