I think most woman prefer "beautiful," especially from someone they dont know that well or are first dating. Its kinda personal I believe to call someone beautiful compared to hot or sexy, and shows that the person calling the other person beautiful has genuine feelings. But in an intimate relationship I wouldn't mind being called sexy or hot.
Hot or sexy. I never get called that apart from one special person. She knows who she is. Beautiful is fine too but it's seems rather feminine and geared much more towards females. I am starting to appreciate the word handsome more now too though.