Watched it with my wife last night and a full theater, mostly of geeks like me. Thought it was a blast.
A few little notes:
1. Captain America shield "easter egg"? That wasn't an easter egg. That was HILARIOUS. It was up, in your face, can't miss this, hey look here! Easter eggs are at least kind of hidden.
2. Tony Stark invents a new element. No name is given, but I have a sneaky suspicion what it will end up being: vibranium. It would allow Marvel to work around the alien substance angle in future movies. Just a hunch, but it sorta makes sense.
3. Loved RDJ. He really is perfect for this and I'm beginning to wonder if he's maybe the most talented actor of our time, especially if you look at the diversity of his roles as of late: Tropic Thunder, Sherlock Holmes, Iron Man. Great work in all.
4. Loved Justin Hammer's character. Played the "CEO who doesn't understand his work really" very well. I got the impression that he claimed all the successes of his company's engineers without really understanding them. Was hilarious when he tried to dance out onto the stage and the expo- clearly trying to emulate Stark, and even doing so badly.
5. My wife was very happy that Pepper and Tony finally got together in the end. Me, not so much. Just doesn't seem right.
6. Disppointed that they "cured" Stark. I always liked the "I'm going to leave my mark because I'm slowly dying angle".
7. The chemistry between Potts and Stark was great again.
8. Agree that Black Widow seemed extraneous. However, I'm thinking that this movie was simply a way to introduce her to the Marvel Big Screen Universe. It was awesome though when she started to seriously kick ass. It didn't even look like she was exerting herself, so I doubt we've seen what she's capable of. One other note on her: yes, she was Russian originally. However, remember they have turned SHIELD into an American organization, as opposed to a global one. It would make sense for her to be American in this incarnation. She needed MUCH more screen time in that catsuit
9. AM I the only one who thinks that Garry Shandling looks like crap? I barely recognized him as Sen. Stern. He played a senator so well that I thought he WAS a senator before I recognized him. I also noted that the movie seems to make a bit of a political statement there, an inditement on how politicians like to say only what they need to prove their cases and omit anything else that may disprove their point. THink there was a jab at the media in there,too. Oh, and I SOOOO want that phone Stark had in that scene..

10. Naturally, everyone left in the theater at the end of the credits clapped when they saw what had been found in the dig.
11. SMJ as Nick Fury was pretty good. Nothing overwhelming, but good.
All in all, a FUN FUN FUN movie. It seemed to me that this movie is there to set up other movies, not just IM3 but Thor, Avengers, etc. Definitely going to see it again to get some of the parts I missed!