I'm not sure I can pick just one....
These are some that come immediately to mind because they are such iconic performances by these actors--these characters they brought to life on the screen are indelible and memorable.
Peter Sellers as Inspector Jacques Clouseau in the Pink Panther series of films.
Kathy Bates as Annie Wilkes in
Misery.
Peter O'Toole in
Lawrence of Arabia.
Audrey Hepburn as Holly Golightly in
Breakfast at Tiffany's.