The Distress Watcher has a list of 8 Top Miscasting in Movies. And, I agree with him for the most part. I wanted to mention a few from his list.
Arnold as Mr. Freeze: Yeah, this makes the movie even worst, and Patrick Stewart should have played the role. Instead, we get Arnold playing a supposedly intelligent scientist. I think not, Joel.
Johnny Depp as Willy Wonka: I have to disagree. I like the more mean-spirited Wonka. I’m not a Tim Burton fan, but I think he got this one right.
Colin Farrell as Alexander: Couldn’t agree more. Except Oliver Stone’s movie was doomed no matter who was in charge of the role. The movie was bloated and poorly constructed. Just like many of Stone’s recent movies. Stone made to the decision to cast Farrell and paid the price. Stone needs to retire.
Rosie O'Donnell as Betty Rubble: Rosie really got the voice down and sounded just like her, but the weight thing was major problem. Betty was very skinny, and then you have Rosie. To be fair, the current state Rosie is in today, she would have never gotten the part.