If it was Jim Carrey, it would have ruined any chance at all of me going to see it. That man's antics get on my nerves, and I imagine he would really have felt the opportunity to cut loose with them, what with it being a children's story and all.
I really really loved Gene Wilder as Willy Wonka. I thought he was absolutely perfect. In fact, he and Johnny Depp are both right at the top of my 'favourite actors' list. They're both so talented, and easy on the eyes to boot.