Casting

Only a small handful of movies have me cringing on some of the casting choices. Since this is one of them, I'd like to see what changes could be made.
If you were in charge of casting, who would you choose? Main characters only. I'll use my choices as an example:

Becky Fuller: I thought Rachel McAdams was perfect. Character was supposed to be annoying, and McAdams nailed it. I'd keep her.

Mike Pomeroy: No, no, no, no, no. I like Harrison Ford, be he is NOT this character! I was thinking more along the lines of Michael Douglas.

Colleen Peck: Diane Keaton? Nope. I'd have Patricia Clarkson fill the role.

Adam Bennett: Any pretty boy could fill the love interest. How about Hugh Grant?

Jerry Barnes: Jeff Goldblum kind of annoys me. But somehow, he seems perfect for this role. I'd keep him.