I know this is an atypical message. But people who vote because they do/don't like his hair or her laugh or his name or his dry speechifying are the sort of people who stuck us with Dubya. If your candidate selection method includes whether he's the kind of guy you'd like to sit and have a beer with, please back away from the booth. Go play a video game or something and leave elections to people who know what they're doing.
(Of course, D.C. Simpson said it better back in 2000.)
Yes, ideally, everyone would vote based on rational analysis of the candidates and their positions. Just showing up to vote does not guarantee that. A low turnout is not, in and of itself, an inherently and entirely bad thing; it is merely a symptom of any of several possible factors.
For example, even those who do try to be informed voters sometimes serve just as well by not voting. My city recently had an election for city auditor, and there was literally not one factor to any of the four candidates that gave me reason to vote for or against anyone. I was not qualified to choose a candidate in that election, and I did not. My vote would literally have been meaningless.
Today's election is for the primaries, which introduces another factor: I am not myself a member of any party. Primaries are the method by which each party chooses who will represent it; for the most part, I'm inclined to leave them alone to do that. I do not have a strong objection to any of the candidates of one of the major parties; I do have strong objections to all of the candidates of the other major party. (Yes, I could engage in strategic opposition voting ... but I am not especially comfortable with the idea itself, and for various reasons I wouldn't be able to do it in this case regardless.)
So: if you know what you're doing, please exercise your right to vote. But please don't go out and vote for someone for bad reasons or no particular reason just so you can say you voted.