Don't make me register to vote. I bailed as soon as I saw that. Just use cookies to identify users. If you get popular enough that you start to see abuse, deal with it then.
Colors not very cheery.
Titles alone are not enough to explain polls (e.g. Who's the bigger train wreck?) Why not put the options on the frontpage with the title instead of making users click through to see them?
I observed that search doesn't work on option's. So although "which cola drink do you prefer? " has pepsi as an option .. searching for pepsi yields nothing. The reason it's important to have this is often I'm looking for what people feel about some product (pepsi/iphone/ubuntu) etc I don't want to guess what the question is.
Also I don't know what your monetization strategy is .. but I would hate to see something influence the choice of votes. like this http://www.betabooth.com/poll/What-Non-cola-Sugary-Drink-Is-... If you want to have adverts make it non related to the questions asked.