I liked Katherine Heigl's dress as well -- yes, she looked great. Between her dress and Anne Hathaway's, though, I have to go with the latter -- if only because it's a little more unique.
Based on what I've read so far, the critics weren't really liking Saoirse Ronan's outfit. That's too bad -- I thought it was really cute. Especially given her age.
I'm looking over a list of the "worst dressed" now, and it includes:
Tilda Swinton
Julie Christie
Jennifer Hudson
Diablo Cody
Rebecca Miller
Ellen Page
Jessica Alba