Anthony Hopkins as Hannibal Lecter, the dude out performed the books.

Alan Rickman is Snape. Always.

Jim Carrey as the Mask.

Robin Williams in Good Will Hunting, or most any role he had.

Rowan Atkinson as Mr Bean.

Sigourney Weaver as Ripley.

John Cleese as Basil Fawlty.

PumpJack_McGee:
Was always surprised Cleese didn't give himself an aneurysm playing Fawlty. Imagine even just pretending to be that high-strung all the time.

James McAvoy in Split.

Pitiful_Winner2669:
It's so good it makes me uncomfortable to such a degree. Incredible performance(s).

Cristof Waltz/ Hans Landa.

Shumuu:
Actually Tarantino wrote Landa and after seeing actor after actor try it he believed the character to be "unplayable" because no one could pull it off. Well, thank God he found Waltz because wow!

Harrison Ford. Indiana Jones and Han Solo.

Far-Government5469:
Harrison brought just the right amount of incredulity to his circumstance to sell them.

Heath Ledger's Joker.

FloydsForked:
This is the one for me. The most epic performance of all time.

Sylvester Stallone, Rocky.

KeyKick7759:
I agree I've enjoyed other boxer films but none have ever got to me like Rocky did.

Patric Stewart/Picard.

craigerstar:
Stewart is the biggest reason for the success of a Star Trek reboot. If not for Stewart's Picard, I believe every Star Trek vehicle made since would not have happened or been some low budget hatchet job, including the current Chris Pine movies.

Bryan Cranston as Walter White "Heisenberg".

Sharp_Ad_6336:
The fact that he was able to break the mental association we all had of him as Hal from Malcolm in the middle is the true tribute to how well he nailed that role.

Johnny Depp as Captain Jack Sparrow.

Prof_Walrus:
The fact they're trying to replace/reboot him is a guaranteed box office flop.
anonymous:
The role was actually written for Hugh Jackman but Johnny Depp had more star power.