You have more than two choices.

The Democrats appear to think that they can win this November by pointing out that George W. Bush isn't a member of their party. They are trying to position themselves as the only alternative to two more years of Republican control. But that simply isn't the case - in fact, voting for Democrats isn't too much different from voting for Republicans in the grand scheme of things. To really show how sick you are with the Republicans (and the Democrats), vote for a third party. If you want to run your own life, vote Libertarian. If you want the government to run your life, vote Green. If you're a crazed fundamentalist, vote Constitution. If you agree with one of the other more niche parties, vote for them. But if you're discontented - which, if you're an American, you statistically probably are - don't vote for Republicans or Democrats.