I'd have to say that although the movie wasn't all that popular, Gary Sinise as George Milton and John Malkovich as Lennie Small in the 1992 version of "Of Mice And Men" were pretty close to perfect.

 

 

As much as he annoys me, I'd also suggest Robin Williams as Sean Maguire in "God Will Hunting."

 

I'd also have to second folks thoughts on Liam Neeson as Oskar Schindler in "Schindler's List", most all of the case of the original "Godfather", Val Kilmer as Doc Holliday in "Tombstone", and Sean Penn as Sam in "I Am Sam".

 

Anybody seen "Shine"? Geoffrey Rush was pretty darn flawless in that one...

 

Adding to my list:

 

Gregory Peck/Atticus Finch "To Kill A Mockingbird"

Paul Newman/Luke Jackson "Cool Hand Luke"

Steve Martin/Navin R. Johnson "The Jerk"

Spencer Tracy/Henry Drummond "Inherit The Wind"

Bill Murray/Phil Connors "Groundhog Day"

Philip Seymour Hoffman/Truman Capote "Capote"

Roger Rabbit as Roger Rabbit...seriously, who else could have nailed that part?

 

C'mon...Bugs Bunny would have had that role, if not for prior commitments!