David Bowie as Maglor - He can sing and he's not a bad actor, as seen in the Labyrinth (yes, I'm one of those girls

) but it'd be ridiculously comedic...dance magic dance and all that.
Also, Dick Van Dyke as Daeron...once again, not a bad actor or singer, but the only thing I would be able to think of was Burt from Mary Poppins. Oh it's a jolly holiday with Luthien....