Shani, I would like to second SM70's remark. I always vote but my reason for voting can change with every election. 2000 was "stick man" and the "chimp", neither a good choice imo, so I voted FOR the Supreme Court. 2004 was a completely different motivation. I was voting for anyone BUT. I'm sure you're impressed with my voting batting average.
Examine what political values are most important to you and try to match them with a candidate, if possible. Stand firm for your choice during the primaries for the reasons Jazz gave. The general election is the best place to show your disatisfaction with the candidates. Writein the candidate of your choice, rather than opting out. A missing vote doesn't say anything about your intention. A writein says a great deal.