I was reading a review of "Man in a Net", an old Alan Ladd movie that really wasn't very good at all. It was in his later years when the booze really had a hold on him. The guy referred to Ladds acting style as "The Cigar Store Wooden Indian style of acting"! It was hilarious, and right on target. He was just trying to make some $$$, he had zero interest in the movie, you could tell.
Richard Burton was another I just didn't get the big deal about. He and William Shatner seem about on the same level in my mind, and I know that's blasphemy! Being "intense" is fine, but come on!
I'll give you a couple people that really can act. Geoffrey Rush, the bad ghost pirate captain in "Pirates of the Carribean", but also the protagonist in "The Kings Speech". I couldn't beleive it was the same guy! Edward G Robinson, watch him in "Key Largo" or something and the in "Our Vines have Tender Leaves". It's like it's not even the same guy. Paul Muni is another that was like that. None of them were naturals at the roles like Barry Fitzgerald in "The Quiet Man" or "The Naked City", but they weren't playing anything like similar characters. I dunno, those guys impressed me I guess.