Hayden Christiansen has got to go--he can't act and then he's not all that cute to begin with.
It would've been interesting if they picked DiCaprio to play Anakin, which is what they wanted to do, but I think what would've been best was for them to go with a handome, talented "unknown" who isn't Hayden Christensen.
Ewan McGregor as Obi-wan was another mistake, and someone shoo Samuel L Jackson away. :/
Padme is just fine with Natalie Portman--she has talent and beauty (even though the scripts have neither).