I saw this movie yesterday, and boy did I waste 6 dollars (matinee showing). Dane Cook was okay in his role, but didn't really do anything to make me think he should ever be a leading man again. He was great in Waiting, so I think he should stick to bit parts. Dax Shepard was actually pretty good, but not good enough to save the movie.
I hate to pile on to celebrities who already get ripped on all the time, but even I have to admit that Jessica Simpson is one of the worst actresses ever to live. She was so awful in this movie, not showing hardly any emotion. Her scene with Dane on the hammock talking about her big ears is excruciating.
The movie missed far more than it hit with the comedic aspect, with Andy Dick's character being a particularly bad attempt at comedy. The climax of the movie is so illogical and silly that you just have to shake your head and laugh.
I know I sound like Stagger Lee in this post, but please avoid this movie at all costs.
My review: http://www.hybridmagazine.com/films/0405/hitchhikers-guide.shtml It was good but also disappointing. The romance was lame. Sam Rockwell's Zaphod was a lame imitiation of W. without being cool at all.