any single scene, the JLC striptease in true lies is in my top 10, but the #1 single scene for me comes from a South Korean Witch film i saw a few months ago(if showtime ever run's it again i'll give you the name of it), where this blind girl's mother goes to some school official to get the bullying of her daughter stopped, and just what the actress wore and how she just used her body language, damn
as for sexiest charater as a whole, i'd have to say that girl from the movie "Secretary"