They did a good job with this one. It wasn't quite as good as Spiderman 2 or the Dark Night, but it was a solid performer and still quite enjoyable. As a comic lover I was particularly appreciative about how they incorporated all of the other movie projects that they're working on.
Normally, having more than one villain is a terrible idea, but the truth is that we have one 'super villain' and two minor villains in the form of Hammer and a rogue senator that wants to take Stark's armor. I also like the fact that they addressed in a somewhat realistic fashion just how much the government wouldn't like the idea of such armor being in the hands of a relatively unregulated private citizen; even a billionaire.