I did pull the lever for Nader in 2000, but as a participant of the Nader-trader program. MD was a Gore-safe state, so I voted Nader in exchange for someone in WI (if memory serves) voting Gore.
While I appreciate Nader's work as a consumer advocate I was less than impressed by his political activism. I listen to his monologue at JHU couple of years ago, which struck me as an incoherent rant against pop-cultural icons (Coca Cola, McDonalds, etc.) that are ordinarily the subject of derision of the social class that can afford sending their kids to Hopkins, rather than a serious political program. I was quite disappointed by his subsequent unwillingness or inability to build a grass-roots political movement for an alternative party (Greens?) along the lines of PIRG (which shows that he capable of serious grassroots organizing if he wants to). In short, Nader seems in the business of selling Nader rather than promoting public good of any sort nowadays.
Another thing: my approach to political participation is instrumental rather than religious/ideological. Unlike many folks on the Left (including this list) who see political participation as an expression of their faith, I see it as a mere means to an end, a tool if you will. It is hard to compromise on one's expression of faith, but as far as tools are concerned - you use whatever is available. A monkey wrench will do, if you do not have better and more specialized tools handy.
For that reason, I have no problem voting Democrats, because they are the best political tool available in the US. I would like to have better political tools, such as a bona-fide social democratic, labor or green party - but that tool is simply not available here. What we have is mere concepts or models of such tools, not the tools themselves - like a toy truck vs. the real thing. But until various toy political parties in this country become the real thing, Democrats is the best, albeit a bit blunt, tool to do the job.
Wojtek