Thor was pretty much exactly what I expected. It was entertaining and action packed and Branagh definitely brought a certain Shakespearean class to the film that helped a great deal. But it wasn't spectacular and fun like the first Ironman or mind blowingly awesome like The Dark Knight, so as a comic book film it lands somewhere in the land of average to pretty good.
Thor is about the God of Thunder. He's kind of a smug, cocky, frat boy "god", so he gets kicked out of Asgard by his dad Odin and sent to earth to learn a little humility. There he meets the lovely astrophysicist Jane (Natalie Portman) and falls in love with her. I mean who wouldn't? They don't make astrophysicists like this everyday.
The film did a few things really well. The acting was believable, the CG was pretty amazing, and for a comic book film, the dialogue was pretty good (there were a few cheesy lines, but on the whole it was well written). Thor also had the challenge of literally telling two stories in two completely different realms and I think it was successful at moving back and forth between the two. Also, this. Well done sir.
Unfortunately the movie had a few failures too. First, I think they spent all their money on CG and forgot they needed to build some real life sets. That small town was ridiculously cheap looking. Also, he falls in love with Jane. What? I didn't feel like they spent enough time for that to work for me. Maybe on a "sacrifice for humanity, cause hey, she's hot and nice" but not on a "I'm mourning that I live in Awesomegard now and really want to go back to Earth and see Jane" level. Although I think the movie flowed well between Earth and Asgard, I think the elaborate story did a disservice to the relationship between Jane and Thor. Especially since I just read about Thor's comic book origin story and it's nothing like the movie and develops the relationship between them a lot more.
Thor had a really selfish stepbrother named Loki that tries to kill him. They battle and it ends with the rainbow bridge** to Earth getting broken. (Although *bonus scene*, not before Loki falls back to Earth). Thor is "stuck" in Asgard and can't return to Jane like he promised. Which seems to make that whole commitment to S.H.I.E.L.D. pretty shallow right? How is this guy going to be an Avenger? I bet they figure this rainbow bridge thing out. I mean the film even ends with text that says "Thor will appear again in the Avengers", so yeah, not a lot of suspense there.
I enjoyed watching this movie and think most fans of the genre will too. I don't recommend it in 3D because it just doesn't feel intended for it. It's a pretty strong 3 out of 5.
**BTW, Thor calls it a "rainbow bridge." I didn't make that up.