Iron Man 1 was fun, Iron Man 2 was forgettable and bogged down by universe building, Iron Man 3 was a disappointment and some of the plot elements were an insult to the audience. I'd say Iron Man has only been in two good movies: Iron Man and The Avengers.
In fact, I wasn't all that big a fan of the Marvel Cinematic Universe until Phase 2 with the release of The Winter Soldier.
Going through the franchise:
Iron Man - great superhero movie, probably one of my favorite origin story films next to Raimi's Spider-Man and Donner's Superman
The Incredible Hulk - Much better than the previous Hulk movie and I liked Edward Norton, unfortunately the plot itself wasn't that great and the movie made little impact on later MCU movies. None of the characters aside from Bruce Banner appear in later films, and even then they recast him
Iron Man 2 - Boring and forgettable. I thought it was bogged down by universe building, I wanted Ten Rings and the Mandarin - they gave us a teaser for upcoming MCU movies.
Thor - Good standalone movie, not bogged down by universe building. While not my favorite MCU movie, I did like how it was contained and had lots of interesting characters and locations.
Captain America - One of the best phase one movies, like Thor it was a great standalone film and I thought they did a good job with the origin and sending him to the present day. My only gripe is that we won't get anymore period movies from the franchise unless they employ time travel.
The Avengers - Solid popcorn flick that did a good job mapping out a plot that included all the characters. The story itself is pretty simple, which I think works for a movie that is more about bringing all these characters together than trying to weave some complex narrative.
Iron Man 3 - I hated this movie. So little Iron Man, so many lame plot elements, weak villains, weak ending. Just... ugh, why did I see this in theaters...
Thor 2 - I recall enjoying it at the time, but as the months pass, it was pretty forgettable. Not as good as the first movie, but still enjoyable enough. I'm not the biggest Thor fan and don't expect much from the character, so I guess you could say I'm easy to please when it comes to his movies.
Captain America: The Winter Soldier - One of the best Marvel movies and best of phase 2. For once they didn't follow a template! I loved the Jason Bourne style espionage, and the evil computer Nazi. Unlike other MCU movies, this and the previous Captain America work well on their own. Just regret not seeing it in theaters.
Guardians of the Galaxy - Definitely the weirdest MCU movie to date. If you're sensing a pattern here, yes I like movies that work well on their own and GotG does that very well. Outside of the Collector and the other infinity stones in past movies, this movie is good in or outside the MCU. My only complaint is that it IS may too similar to The Avengers in story structure and I didn't care about the planet they were protecting in the end. Also, are all the humanoid characters humans? That confused me.
So overall, the Captain America movies are my favorites, Iron Man, GotG, and The Avengers are fun, Thor is flawed but enjoyable, the Iron Man sequels are crap, and Hulk deserves better.
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My favorite current series of comic book movies is actually the X-Men films. Sure the franchise has had a few pieces of crap (X3 and X-Men Origins: Wolverine) but I think the first X-Men is a solid early ensemble superhero movie, and X2, First Class, The Wolverine, and DoFP are excellent.
