It's bright, it's colourful, it has some laughs, thrills and spills and when all is said and done there are certainly a lot worse comic book films out there in the mix than Thor.
Although it struggles at times to evenly balance out the Earth and Asgaard set portions of the story (at times clumsily flitting between them both) the strong enough performance by Chris Hemsworth as Thor keeps you engaged. The visuals and production design are pretty impressive in places (especially Asgaard) but that's to be expected nowadays. It's not as breezy and effortless feeling as Iron Man or even 2008's The Incredible Hulk felt, but it's less laboured than Iron Man 2.
Obviously there's an element of pre-planning for the first The Avengers film due out in May 2012, but for the most part the film manages to avoid feeling too much like it's just another part of the required jigsaw and find it's way to becoming an enoyable enough blockbuster on it's own.