Who's the best actor/actress ever?

[Graybeard]

9. For me it's a close call between two.

William Powell and James Stewart.

William Powell never gave a poor performance IMO. In all of his 'tipsy-sophisticate" Thin Man movies and others in the 1930s to wonderful comedies like Life With Father and Mr. Peabody and the Mermaid in the 1940s and his final roles in How To Marry A Millionaire and Mr. Roberts in the 1950s.

James Stewart worked into the 1980s and if I had the 'desert-island' choice of only one actor's movies to watch it would be Stewart. From the light weight comedies and socially relevant classics of the 1930s and 40s (Mr. Smith Goes To Washington, It's A Wonderful Life) to the intense 'psychological Westerns' of the 1950s to his wonderful work with Alfred Hitchcock and one of his best, Anatomy of a Murder.

My two 'best' actors.