Oh, I was so excited about Sweeney Todd. It was going to be great. First, Johnny Depp as the demon barber of Fleet Street, and then Director Tim Burton got Sacha Baron Cohen to be Adolfo Pirelli, which just kicked ass, casting-wise. Or so you'd think. You'd guess that Burton would have discovered this before casting him, but it seems that Cohen can't sing, so he's been told to rap his songs.
That sucks. Big time sucks. Pirelli's character is a cool one, but his songs are really awesome, and kind of castrati in nature, which, in case you don't know, means that they're really high. Not at all condusive to rap. I like rap, but in this case, it's a bad choice. I wish they'd cast someone who could sing.
Dark Horizons.com: Cohen Not Singing In "Sweeney"