Taeylor: I've heard dozens of stories of (British) people who were absolutely convinced that Marsters was British and didn't buy that he was an American until a few interviews were shown.
No, Maggie's really not needed in the movie. If they want to tell the story in two hours or so, they can quite easily leave out Maggie and do an HoDS-esque retelling of the initial Barnabas storyline. Aside from that, Kathryn Leigh Scott looked really good in that role, but I don't find Keira Knightley the slightest bit attractive, probably because of the bad nose job. Just my opinion. If they are going to do Maggie in the movie, Emmy Rossum is still my ideal.
Charllize Theron is my number 3 choice for Angelique, after Sarah Michelle Gellar (1) and Halle Berry (2).
I also think that Alan Rickman and Susan Sarandon are too old for those roles. I see Julia and Roger as being in their mid-40s, and Rickman and Sarandon are both in their mid-60s.
Good suggestion of Edward Norton for Willie. I can see that.
I'm stil looking for who I think would be a good Carolyn, though. None of the suggestions posted here have really clicked with me as, "Oh, yes, she's the one" for her, no offense intended.