Ever since they announced Robert Downey Jr. as Tony Stark, I've been excited about this movie. Did you see this commercial during the Superbowl? It's the first time we've seen the modern armor in action, doing anything other than flying. It's also the first time we've seen RDj in the armor getup.
I think I echo a pretty universal sentiment when I say that Robert Downey Jr. Will make this movie. Granted, you have to keep in mind that he's perfect as the Platonic ideal of Tony Stark, not so much as the Ultimate or ultimate dickhead Tony Stark Marvel is publishing right now.
Marvel movies have been so hit-and-miss, with at least two stinkers (see: Ghost Rider, X-Men 3, Fantastic Four 1 & 2) for every good film (see: X-Men, Spider-Man 2). I think this is going to be one of the good ones, if not the best.