It would be hard for me to definitively answer this question because, A) I've always preferred and watched homemade stuff rather than professional porn and thus am not familiar with most of the actors and B) when I did view exclusively professional porn it was during the let's just say "discovering porn/videotape stash days" and with a single exception, I couldn't even remember any title, let alone who was in them.
A particular example would be the one movie that consisted of a scene of three women who answered the door to three guys whose car broke down (sounds like every other porn plot doesn't it
). One woman had curly black hair, one was a blonde where the carpet matched and the third was a brownish brunette; none of whom I could name. It was the scenes with the third women that I got off the most on. Even today seeing her doing a reverse cowboy and watching the camera pan from the dick driving into her bush up to her torpedo shaped breasts to the look on her face and then slowly back down again will always be seared in my mind and I wish I could find out the name of the movie so I can jerk off to her again (if anyone might have a clue and can help a guy out, I be indebted
). Thus whoever she was, would likely be the one actress I came the most for.
However, if one was to insist upon a specific name, I guess I'd have to go with the runner-up of Constance Money as her movie "The Opening of Misty Beethoven" was actually the only pro-porn movie I owned (in VHS no less) and while it was primarily bought to be watched with the wife, there was times when I'd jerk off to it when I had time alone.