It just didn't seem right to have a list of actresses and not have a companion list of actors, so here goes. Same rules apply:
1. Nick Cage - Quite possibly the most annoying actor on the planet. He's got the strangest facial contortions, and it always looks like he's constipated. I really can't stand the shtick he does in (what seems like) all his movies. Though I did like the Rock, it was more for Ed Harris and Sean Connery than Nick Cage.
2. Keanu Reeves - It'd be really easy to explain this away simply to "whoa," but that's selling his lack of talent short. The guy sounds like he's reading his lines to himself (much like a 5 year old sounds when he's reading a script). I think he's one of those "bad actors who somehow gets into decent movies."
3. Leonardo DiCaprio - I'm not quite as adamant about this one. I though he was excellent in What's Eating Gilbert Grape, but I've been less than impressed in all his other movies. He strikes me as a "like me because I'm cute" actor who really has nothing more than charm to go by, and not necessarily a whole lot of that.
4. Billy Bob Thornton - He annoys me, and I find him rather creepy. I suppose he's good at what he does, it's just that what he does is annoy me and creep me out.
5. Mike Myers - Mike Myers's "Look at me, I'm being subtle here" thing wasn't funny in Wayne's World, and it's gotten less funny as time goes on. He makes kids movies, which you have to edit because so many things that SHOULD be over kid's heads, but aren't necessarily, are in them. I find him more annoying than Adam Sandler (Who I don't like but won't include on this list) and less funny than Jim Carrey (who I used to like but am losing the taste for), and not particularly witty, I don't think. I guess to sum it all up, I think he's full of himself.
That's all for this one, I'm sure I'll add more to it as I go along.