[First of all, I'm a little annoyed to notice that I've seen about 25% fewer movies so far this year than I did last year. While that means that this year I haven't seen as many Ghost Riders and Disturbias, it also means I've been missing the occasional Reign Over Me or Away From Her, so I hope to get caught up soon.]
Perfectly entertaining, mostly thanks to Downey's charming movie-star performance and Jon Favreau's handling of tone and comic timing. I can't say it rises to the levels of the absolute best superhero movies, but that's partially just a matter of personal taste: for me, the most interesting superhero stories are the ones about outsiders - Peter Parker's loneliness, the X-Men and their estrangement from society, Bruce Wayne's obsessions. Tony Stark, on the other hand, is a total insider, the man who has everything except superpowers, so he builds his own. And that means that a lot of the movie is given over to lifestyle porn, as we ogle Stark's Malibu house and car collection and female conquests (although for a multi-millionaire, his lifestyle isn't that lavish - he only has five luxury cars in his basement? Get a job, hippie).
The drama of the movie is split in two: the first half of the movie is given over to making arms dealers cool again, which is basically a substitution for making America-as-military-power cool again. Tony Stark learns to be a little more careful and focussed in his use of power, saving women and children from Mideast thugs, and certainly that's how we'd all prefer to think of ourselves as Americans right now, bogged down in two wars, and this part of the movie is one of the major reasons I think the movie is going to be cathartic for audiences this summer (and profitable). The other major reason is the savvy decision to shift the movie, midway through, away from the Mideast storyline and into a more conventional kill-the-mentor storyline, the same one they've run through in the Spider-Man movies plus Hulk and Batman Begins, so we don't have to think too much about terrorists. It's a smart move but it basically lets us off the hook for our complicity in Stark Industries' potential war crimes. But it's a summer action movie, so I don't want to get too Village-Voicey for a movie that is, in general, fine.
Favreau is obviously more comfortable working with actors than he is at coordinating action scenes or manipulating complex narratives (like the super-clumsy exposition-by-video at the film's opening), and I'm glad he kept the movie as low-tech as he did, with a lot of practical effects in addition to CGI. My favorite scene in the movie, Pepper Potts assisting Tony Stark with open-heart surgery, was performed with a good old-fashioned fake rubber chest and two actors who know what they're doing. That said, I wish Paltrow, Jeff Bridges, and Terrence Howard were all given a little more to do in the movie than just run through the plot points. I can already see Howard suiting up in the next movie while Downey's on a drunken binge. Oh, and the Nick Fury cameo? Whatever. Let's see a good Thor movie first.