Too hard to name just one...
Jack Nicholson (Here's Johnny!!!)
Gary Oldman (I'm still not convinced that he played that wheelchair guy in Hannibal. I mean I know it's him but he's just so good you don't even get a hint of it).
Al Pacino (Godfather, Scarface, etc)
Robert DeNiro (Godfather, Goodfellas, and a ton of other stuff)
Sean Penn (Has been doing great performances for 20+ years.)
Johnny Depp (All around good actor who plays a lot of offbeat roles.)
Kevin Bacon (He can really play a sleezeball well. His character in Sleepers still gives me chills.)
Marlon Brando (Godfather)
Sean Connery (the real James Bond)
Leonardo DiCaprio (I thought his performance in the Basketball Diaries was amazing. I know he's got talent. I just wish he would start to pick more roles that let him display it.)
Tom Cruise (A guy who has done a lot of really entertaining movies over the years. Not all of them are Oscar worthy but he has done some great performances. I think he was snubbed at this past year's Oscars. The Last Samurai was the best movie that he's ever done. One day I think he'll get his due.)
Robert Duvall (He seems genuine in all of his roles. I especially like him in Colors.)
Meryl Streep (THE best actress of our time.)
Jodie Foster (The second best actress of our time.)
Jennifer Connely (The third best actress of our time.)
Julia Roberts (She's played a lot of different roles and she adds a warmth to them.)
Katherine Zeta Jones (HOT!)
Rachel Weisz (HOT and talented)