My ten least favorite celebrities, in no particular order...
Rosie O'Donnell - she was fine as a bit actress and as a VH-1 VJ, but then she got her show and her whole existence became being a professional lesbian and liberal.
Ant - Comedian, for pretty much the same reason as Rosie. I don't care what you do in the bedroom, until you make it your entire purpose for being and thrust it in everyone's face. You no longer exist as a man, you exist as a gay man.
Paula Abdul - she's nice to look at, but for the sake of American Idol, find someone else.
Ryan Seacrest - I am convinced he is an alien because no one can do as much professionally in a week as he does without requiring rest. I did like that he mocked himself in "Knocked Up."
Paris Hilton, et al. - so we include Nicole Richie and any of their friends who have no reason to be celebrities in the first place.
Brittney Spears - the world does not revolve around this person.
Brett Farve - we need something new to talk about. Go retire and enjoy the gift you were given when your wife survived her cancer.
Miley Cyrus and her has been father.
Jolie/Pitt - see above, saame reason as Brittney