My favorite picks: 
Johnny Depp as Toot-Toot.   Can't you just see him saying "Harry, have you HAD pizza?"
Alan Rickman as Nicodemus.   If you only think of him as Snape, you have not seen enough of his movies.  There is no one who does elegant menace as well as Alan Rickman.
Angelina Jolie as Lara Raith.  I don't particularly care for her as an actress, but she does have the smoldering sensuality down.
Gary Oldman as Michal.  Just because I love Gary Oldman, and he's a chameleon actor.

Meryl Streep as Mab.  She could even come up with her own accent.   I also think it would be interesting to have the same actress portray both fairy queens.  OTOH, Michelle Pfeiffer has already played Titania once.

(showing my age now)
Billy Crystal as Butters. 
Morgan - Clint Eastwood

As for the rest
If Alexis Denisov plays Harry, I so want Allyson Hannigan to play Lea.  Actually, I'd want Allyson to play Lea either way, but having her play Lea to Alexis' Harry would be hilarious.

Janeanne Garafolo could play Murphy - she has done blonde and she could certainly do the smart-mouth
Karl Urban could play Mac.  Just to get him in the picture.
Sigourney Weaver could play Charity.  She has done blonde as well.

Maybe James Marsters could play Marcone?  Or Bob?

I was thinking about Nicholas Cage as Kincaid, but I'm not attached to it.


Actually, I would prefer to see most of the roles filled by relative unknowns.  Except for Johnny Depp and Alan Rickman.  Those are non-negotiable.

The only way that I would agree to Tom Cruise in a DF movie would be if he played Cassius(?) the snakeboy  Denarian.

I'd pay good money to see the $#@$ beat out of Tom Cruise.