Actually, I think the "biggest asshole" wouldn't be too bad of an idea ... For the most part, I'd imagine that the people who would be voted for in that category know it, and would be proud to win. "Most hated" might get touchy, that's understandable, but I'm not sure about "biggest asshole". Or "arsehole", I suppose.

But then, with either, the people that really dislike the candidate might not vote for them, because they might feel proud to win. You know what I mean? If you hate me, and I would be proud to be "most hated", would you vote for me, knowing I'd be happy to win?

Why not ...

Most likely to be seen on Cops
Most likely to go to jail
Most likely to make it rich
Most cultured
Most violent
Most masculine
Most feminine