I doubt Paris Hilton would get the role, thank goodness. I have yet to see anything of hers.
Cosette would probably go to the likes of Keira Knightly, or Lindsay Lohan/Hilary Duff...Christina Aguilara? She's got the voice chops to go with it...
Or maybe Renee Zellwegger...
Orlando Bloom as Marius. Most definitely...or Ashton Kutcher or someone else who's in the boy craze title these days. Jean Valjean will be someone middle aged and famous. Mel Gibson?

George Clooney? Lol. "On My Own" will be sung by Britney Spears with a baby in hand.
And I guess Fantine will be played by Queen Latifah. It's a given...she's the diva of the movie musical nowadays, the Michael Crawford, if you will...
Sorry for the disturbing picture.
Yeah, I shouldn't even be supposing these sorts of things.
I just went to the imdb website and am looking up the upcoming Hairspray.
Amanda Bynes is Penny? Huh? How? And Billy Crystal was originally signed up to play against John Travolta as the small, but important role of Wilbur Turnblad. Unfortunately, he had other committments so Christopher Walken is currently signed up for the role instead.
Hairspray, IMDB
The guy who played the main character on "High School Musical" is being cast as Link. Not a fan of the guy...he makes weird facial expressions.
And Brittney Snow (Amber Von Tussle)? Does she even sing?
Gotta give props on Travolta-hopefully he's a riot in a dress. And for once, two original Grease (or Grease 2) fames are taking stage together. Michelle Pfeiffer is signed up for Velma. She's pretty good...I can't wait to hear her vocal chops (again). She's only sung in, what...two movies she's done, right? (Grease 2 and The Fabulous Baker Boys)