I saw Thor yesterday, and I have to say that it has immediately become one of my favourite superhero movies, right up there with Nolan's two Batman movies and the first Iron Man.
The first half especially was terrific, visually stunning and superbly paced, with a script that threw in a nice amount of tension and some good laughs. The CGI - Asgard and Jotunheim must be entirely computer generated - was spectacular but never intrusive or jarring. As in the Lord of the Rings movies, I think this is down to a an eye for detail and a carefulness of design; the backdrop is never just a backdrop, but seems a complete world you could step out into. The armour worn by Thor and the other Aesir (my one gripe was that they were always called "Asgardians, as though another strange word to anyone unfamiliar with the myths would break the spell) is an excellent example of the design; on Asgard it matches the magnificent Norse/Art Nouveau aesthetic (Aesir aesthetic..?), while on Earth it seems hyper-real, without being cartoonish.
More than anything, though, the film is made by the acting and the director. There are some fine performances that you'd expect - Anthony Hopkins full of Welsh gravitas, wisdom and understated power as Odin, Natalie Portman doing a nice turn as the obsessed physicist and some excellent support from Stellan Skarsgard and Idris Elba - but all the actors carry their roles well, including huge, handsome bemuscled Aussie Chris Hemsworth in the title role. Yes, those three attributes don't actually count against being able to act (not Idris Elba above), but it's nice not be confronted by 80s action hero wooden acting.
I think a lot of the credit for the performances probably goes to the director. I admit i had some reservations about Kenneth Branagh (yes he can obviously direct, but his one previous bib budget, big scale attempt in Frankenstein was such an utter train wreck and a complete waste of talent) but he shows he can do it. He directs the actors and helps brings the script to life, controlling the pacing superbly and creating the world(s) in which the action takes place. Which is a director's job, of course.
The film isn't perfect. The second half isn't quite as good as the first, purely because it has to comply with some of the conventions of a superhero movie - the set-piece fights and so on - but it's going to take quite a bit to knock this of the podium as my blockbuster of the summer.