Erm, it depends on the tie for me. I tie skinny ties Four-in-Hand and generally tie standard width ties Pratt. I should use the Windsor knots more, though.
Speaking of ties, I've seen in TV shows, movies, and in real life girls tie a tie for a guy who is struggling with it. What's with more girls knowing how to tie ties than men?
Half- (or "Single") Windsor. Only style I could manage consistently, although the quality of the tie affects that. I suppose that I should wear bolos as I'm an Arizonan--it is the official state neckwear.
OK, after looking at the diagrams, I realized that after all these years it's been the Four in Hand. My dad taught (and told) me the knot, calling it a Single Windsor. First thing I ever discovered he mislead me about, and I'm going to promptly forget it; I prefer to keep my memories of him as perfect and unrealistic as possible.