Vincent Vega: Elliott Gould
He was on a roll around this time often playing disheveled characters. Comedically he's right, He would have been fantastic as a strung out Vincent.
Jules Winnfield: Fred Williamson
Cool, slick, intimidating and funny. I think his chemistry with Gould would work.
Mia Wallace: Anjelica Huston
Unique, appropriate look for the role and a strong actor.
Butch Coolidge: Burt Reynolds
An obvious choice.
Winston Wolf: Charles Bronson
A bit older at this point, a guy who looks like he has seen some shit and can handle it no problem.
Marcellus Wallace: Julius Harris
A staple in blaxploitation cinema, all around bad motherfuckin' kingpin energy.
Pumpkin: Alun Armstrong
Nothing screams lowlife British criminal more than this guy.
Honey Bunny: Miriam Margolyes
A filthy foulmouthed lady capable of shouting down a crowd of strangers, great pairing with Armstrong.
Captain Coons:
I want to hear Lee Marvin say this monologue about how he hid a watch up his ass more than almost anything. I think it would be fucking hilarious.
Fabienne: Leslie Caron
Too old by a considerable degree by this point, but really embodied the sweet innocence of the character.
Lance: Antonio Fargas
If you were buying heroin in the 70's, he seems like the guy you'd get it from.
Jimmy: Richard Pryor
I think he would be great in the kitchen scene.