I make it a point to learn actors' names once I've known them in two or more performances I've enjoyed, or in one very significant one. This is why I know names like Christian Kane and Morena Baccarin. It's important to me to know them as a name rather than a vague collection of typecast roles, like "that guy who was a lawyer in Angel, then the tough guy in Leverage and also the Librarians".
I also sometimes deliberately learn the name of "the other guy" in famous movie duos. Like Keanu Reeves and that other guy in Bill and Ted. Even though Alex Winter hasn't worked much since then, I'd hate to be known as just "the other guy", so I do them the courtesy I'd expect for myself.
Mokalus of Borg
PS - Now, if only I could be this good about the people I actually meet.
PPS - I've proven I can do it. I just need to focus.