These are more favourite than best, and are in no particular order:
The Dude - The Big Lebowski
Vincent Vega - Pulp Fiction
Jack Sparrow - Pirates of the Caribbean
Shaun - Shaun of the Dead
Forrest Gump - Forrest Gump
Tony Montana - Scarface
Michael Corleone - The Godfather
Roger Rabbit - Who Framed Roger Rabbit?
Spooney - Dog Soldiers
"The Wolf" - Pulp Fiction
Everyone else in - Pulp Fiction
Big Boy - Dick Tracy
Aragorn - LOTR
Pinhead - Hellraiser
He-Man - Masters of the Universe