Half of a good movie with a heck of a lot of overacting. See the 2-D print as I can't imagine the 3-D will add anything.
Half of this movie takes place in a little sleepy town in New Mexico. The other half takes place in a technicolor Jack Kirby-esque version of Asgard. This makes for several jarring shifts in tone as the movie goes forward. One scene will feature Natalie Portman and friends complaining about the loss of their research equipment (something I can relate to) and the very next scene will feature Anthony Hopkins giving an insane speech about frost giants or rainbow bridges or whatever. It makes some sense in context, but its more than a little awkward when the two world collide. Especially since everyone in Asgard talks like Stan Lee writes. Norse god aliens like their exclamation marks apparently!
The pace of Thor was my biggest complaint. The origin of Thor as a hero comes after he is sent to Earth by his father to learn humility (though this isn't explicitly clear in the movie version). Thor does learn humility and heroism in the movie, but it takes roughly 34 seconds. There really isn't any transition between arrogant, war-inciting Thor and humble, breakfast-making Thor. A single subtitle saying "6 months later" would have gone a long way here. Supposedly there are 30 minutes worth of deleted scenes. Maybe all the charartcor development takes place there. The development of the film's antagonist is less rushed and, as a result, feels far less superficial than that of the main character's.
All and all though the movie is surprisingly entertaining. Though the characterizations are rushed and the whole Asgard thing is a bit silly, the actors have good chemistry and the plot moves along quick enough that my critiques don't really matter. Its not as good as the Iron Man movies but its certainly on par with The Incredible Hulk. Definitely worth checking out on video or at an afternoon matinee. Just be sure to turn your brain off.