If I'd do the film in colour, I'd most definitely go for an intense cinematic effect. But then again, with how quickly my mind changes, probably not. I rather liked the play of colours in the movie Hero (the one with Jet Li), what with the symbolism and all. Memoirs of a Geisha cinematography was also good, and it had, as you say, "interesting shadow" as well.
But I rather like the idea of a black and white film. That, or a dark sepia tone would also help. It's sort of like skimming through an old book, with the pages yellowing with time... Hmm. Sepia gives a rather... priceless feel, just like Les Misérables itself.
And yes, it would be very lovely to shoot the film where the story happened. It would feel very authentic, and since we're on a limitless budget... I'd most definitely wouldn't mind going through the pains of buying lots and rebuilding the places that were mentioned in the book, but were lost, blah, blah. Yes, rant on Savvy.
As for the cast, I'd do the casting myself, and hire people who actually give a damn about being totally canon than just hire Mr-So-and-So because he's been in several films or is hot. Eurgh. I'd choose believable actors, the ones who can actually convince me that they are who they're portraying. I wouldn't mind if they added a bit of their own little quirks to the characters, but not too much that it would dramatically effect the canon-ness of the film. As for Enjolras, however... right. I will shut up now.