I was extremely entertained by this film, and imho it stands right up there with the first Thor film as one of my favorite Marvel films. I'll agree with Mouth that Malekith isn't as impressive as Loki for a bad guy. But his motivation is pretty straightforward and understandable. He pretty much goes directly at his objective without much trickery, so he does seem less interesting as a bad guy. But he never came across as being a non-threat. He was a leader and used what resources he had very effectively. And I don't consider Selvig to be a one note comic relief, he did help out greatly at the end. But I do wonder what he was doing wandering around loose without S.H.I.E.L.D. supervision after The Avengers. But it was overall a good story.
The action sequences were great, the final battle between Thor and Malekith was suitably epic, this was a great film from start to finish.
And speaking of the finish, there are two easter eggs at the end, one before and one after the credits.
And anything else I could say would be major spoilers.
