I guess I wasn't expecting much with this movie to begin with. I generally like Seth Rogen movies, so my expectations were not high.
If you're looking for a well-acted, plot intensive movie, this isn't it. Christoph Waltz's talents are completely wasted, he spends more time worrying about his attire than being a baddie. There was no point to having Cameron Diaz in the movie, it seems like she was simply eye candy for the guys watching the movie. Rogen played Britt Reid like he plays his other characters: goofy, and arrogant. To me I wasn't bothered too much by that though. But I have seen the Green Hornet TV show, and if I was more of a purist, I would be utterly disgusted by what this movie has done with it. The best character was Kato, he was a total bad-ass, loved the Bruce Lee reference.
Overall, if you're looking for a matinee where you don't have to pay full price, this makes for a good popcorn movie. I have no plans to see it again in the theater, as I think it would be a waste of money. Kids loved it though, and we'll be looking forward to having it on DVD.