I realize midterms aren't as sexy as presidential elections, but they really, honestly, genuinely make a difference. The current crop can REALLY make a difference.
It's worth the minimal chunk of your time. It secures your right to complain later. If you're not voting because you don't like anything about politics--well, consider, because you're a non-voter, there's absolutely no reason for politicians to do anything on your behalf. The only way to get your demands met is to be important to the process, and the only way to get important to the process is to vote. Not voting because you want other choices is like not bailing out the boat because you wanted to take a plane. You aren't gonna get your plane, we're all just gonna drown together.
If you're not happy with the way things are going, if you don't like the war, the economy, the state of the world, then don't sulk at home--vote, damnit.
If you love our current policies, if you're convinced that Bush is all that stands between us and weekly bombings--then I also suggest you get out and vote, 'cos otherwise those of us who are majorly pissed are gonna kick you to the curb.
Either way. Just take responsibility. Make politicians fear your power. Vote.