Christopher Walken
True Romance
Y’all keep giving me a chance to play some of my favorite actors. 
Gary Oldman
The Fifth Element
Chris Tucker
sigh
Rush Hour
I hoped you’d play that one.
Tzi Ma
(He’s unseachable but I have to assume that no one has played him. And you’ve most likely seen him in something but don’t know his name.)
[sylvester]You’re deeespicable[/sylvester] - made me resort to IMDB. 
The Ladykillers
(And you’re right, I recognized him as soon as I saw his picture.)
He’s been in a lot of interesting or well known movies, too, hasn’t he. I try to expand our horizons. 
J.K. Simmons
And you did a lovely job, ShibbOleth.
Shame I can’t use a TV show (cough Law & Order cough) for this one, but…
Spider Man
Brilliant bit of casting. He was perfect.
Willem Dafoe
Platoon
Tom Berenger
Someone to Watch Over Me
Continuing with the Law & Order theme…
Jerry Orbach
Brewster’s Millions
Richard Pryor
Stir Crazy
The fact I can think of this without IMDb assistance before 8 am frightens me…
Gene Wilder. (duh!)
Young Frankenstein