Just got back.
I didn't think it was earth shattering, but I did find it very cool. A nice start to a potential franchise. I would of loved to see a little more "Iron Man Action", but the first movie in this sort of thing is almost always the "setup film."
Downey was fantastic as Stark. He really nailed the character, full of the cockiness, style, and swagger. Jeff Bridges was pretty good as well.
Oh and stay after the credits. There is a little scene with a bit of a "surprise" and story arc to it. Not a worthless scene like at the end of the the Pirates of the Caribbean 3.