I saw Iron Man last night on a very large DLP screen, and all I can say is if you have not seen it, you should go while it is still on the big screen!
First, Robert Downey Jr gives a spectacular performance. He manages to play the slick public-figure-type guy, the get-your-hands-dirty-genius-inventor guy, and the "Jon Stewart-ish" witty comic all rolled into one. He really was the perfect fit for the role.
Jeff Bridges also gives an unbelievable performance. The quality of his acting really shouldn't come as a shock to anyone, given his past roles. It's nice to see that he's never really been typecast into a certain kind of role.
The video and sound quality was really staggering. The special effects were good enough that the line between real and CGI is basically invisible, and the overall physics in the movie is really lightyears beyond similar movies like Spiderman. I generally don't mind suspending my disbelief for comic book type movies when it comes to dismal physics, but it was truly refreshing to see mostly-real physics in effect in Iron Man.
I see quite a lot of movies in every genre except horror, and I gotta say this is most likely the best movie I have seen in 1-2 years. A+