Usually I'm more interested in the director, but a few actors jump to mind:
Women:
Veronica Lake - the coolest actress ever.
Grace Kelly - the most beautiful actress ever.
Rita Hayworth - another great beauty, somewhat versatile actress.
Katherine Hepburn - a truly great actress.
Audrey Hepburn - the cutest actress ever.
modern - Julie Delpy (beautiful and smart), Renee Zellweger (always surprises me, I guess she is just very good), Judy Davis (interesting, versatile actress), Hilary Swank (to be determined...so far seems to have potential)
Men:
Jimmy Stewart - great whether doing comedy, drama, or westerns.
Charlie Chaplin - the funiest actor ever (and a great cinematic inventor/director)
Cary Grant - another great at straight-faced comedy and drama.
Woody Allen - acting, writing, and directing genius.
modern - Clint Eastwood, Gene Hackman, John Cusack (another straight-faced comedian...love that stuff), Bill Murray (and another)
Comments:
Brando should be remembered for On the Waterfront, not Godfather.
Modern actresses are really lacking compared to those from the past (in looks, talent, and general charisma), which is very sad.