This topic from Long and Short Reviews was tougher than I expected, because it's been a few years since I've crushed on a celebrity. Having said that, I can remember a few from my past who probably aren't to everyone's taste.
John Barrowman. Yes, I know he's gay, but I could never resist him as Captain Jack and I love a man with a good singing voice.
Gene Wilder and Alan Rickman. I put these two together because they were my Holy Grails as an autograph collector (I got them both, but it took a lot of effort). I could watch Gene and Alan in literally anything and would enjoy myself, although I will never forget Willy Wonka.
Alan Davies. I initially discovered Alan Davies in Jonathan Creek, but found I liked him even better as a comedian, particularly on QI.
Daniel Radcliffe. I'm not a lover of his beard, but I find him irresistible in almost everything he's been in after Harry Potter.
So who are your celebrity crushes?