Is there a presidential vote you regret casting?
(Fess up, Reagan voters!)
I can't say that there's a vote I regret. In '92, the year I turned 18 and ergo my first election, I voted for Clinton. In '96, I didn't feel like I could cast an affirmative vote for him in good conscience, so I didn't cast a presidential vote that year. Voted for Gore in '00 (and while I lament having to vote for Lieberman, I don't regret voting for Gore), and voted for Kerry in '04 pretty happily, though he wasn't my first choice in the primaries.
Actually, Gore is the only first-choice candidate for which I've ever been able to cast a vote, and he picked a veep candidate I couldn't stand, lol. I've never had much luck with finding an opportunity to cast a vote without reservation.