I was watching the movie Arthur the other day; it is a favorite, with several witty performances, but none more so than that of John Geilgud as the perfectly understated Hobson. And it occurred to me that a number of my favorite movies have butlers as memorable characters, so I started making a list. First I discounted any actors named Butler (e.g. Gerard) or characters (e.g. Rhett), and I also eliminated valets (e.g. Jeeves or Passepartout) from the possibilities, as they are in my limited New World understanding different from butlers, and any of the wonderful Television performers (e.g. Eddie Anderson, Roscoe Lee Brown, Ted Cassidy).
Here is my list, in rough order of delight:
1. William Powell as Godfrey (My Man Godfrey)
2. John Geilgud as Hobson (Arthur)
3. Antony Hopkins as Stevens (The Remains of the Day)
4. Eric Blore as Bates (Top Hat)
5. Paul Bettany as Jarvis (Iron Man, etc.)
6. Forest Whitaker as Gaines (The Butler)
7. Michael Gough as Alfred (Batman)
8. Hank Azaria as Spartacus (The Birdcage)
9. Denholm Eliott as Coleman (Trading Places)
10. Erich von Stroheim as Max von Mayerling (Sunset Blvd)
I suspect there are more I can't think of. If you can, please comment, as I would like to create the definitive list.