I know people don't care too much about rankings, but here are mine:
1) Iron Man - I still feel like this is the best paced and structured out of the bunch, with a clear character arc for Tony, and probably some of the best humor.
2) Avengers 1 - The reason I love this one so much is because, yeah, it was the first time we're seeing Cap, Thor, Iron Man, Black Widow, and Hawkeye together being the Avengers. Nothing has come close to that.
3) Guardians of the Galaxy - It was a fun movie, with a different tone than the other Marvel movies, featuring a lesser known group of heroes, but still leaving a strong impact with me.
4) Captain America: The Winter Soldier - It probably has the best plot of the series so far, with a story that is genuinely interesting and unpredictable, with real ramifications for the MCU. It also served to highlight why Cap is the leader of the Avengers. It was the movie that really made me like Steve Rogers as a character, not just as Captain America.
5) Avengers: Age of Ultron - A fun, entertaining movie that mainly suffers because of the heavy editing it underwent to get the running time under control. Ultron was a solid antagonist, and Spader did a great job. It was nice seeing Hawkeye, Black Widow, and Banner/Hulk get more screen time.
6) Iron Man 3 - I really liked this one. I enjoyed the PTSD storyline for Tony, and the humor was surprising, considering how dark the trailers made the movie feel. I thought it had a great arc for Tony. The Mandarin twist was amusing and fun. He's a racist stereotype in the comics, so having him done away with in this fashion worked for me.
7) Captain America: The First Avenger - As a not big fan of Captain America, I was surprised at how much I enjoyed this. It did a good job of establishing Steve as a good guy, with a desire to do right for his country. Red Skull was a cool villain, and the lead in to The Avengers was nice as well.
8) Thor - I was not expecting this movie to be pulled off well. I always thought Thor was kind of an out there character, but I highly enjoyed the "fish out of water" aspect of his character in this movie, and wish we had gotten more with that before he became accustomed to Earth and his desire to protect it. I strongly disliked the romantic plotline with Jane, because I felt Helmsworth and Portman had very little chemistry. Skaarsgard was great it in as well.
9) The Incredible Hulk - Hulk is a hard character to do justice in a stand alone, solo film, but I felt this movie did a good job of dealing with Banner's Abomination is a good choice for a first villain. Ed Norton was a very good Banner as well, but I still prefer Ruffalo's take on the character.
10) Thor: The Dark World - The problem with Thor's movies is that sometimes they feel completely disconnected from the overall goings on of the MCU. The Dark World was entertaining, but still felt ultimately inconsequential to the main plotline. I always enjoy seeing Tom Hiddleston and Kat Dennings, though. It's a shame that Eccleston's villain was so mediocre.
11) Iron Man 2 - I didn't hate this movie, because it had Sam Rockwell in it. He is always a hoot to watch. Mickey Rourke was wasted as Whiplash. It's not that Whiplash sucks, it's that they didn't really do enough to make him a genuine threat for a dude that wears a suit of armor. I also love Don Cheadle as War Machine, and think he and Downey have as much chemistry as Downey and Howard did in IM1. While it's my least favorite of the MCU flicks, I didn't outright hate it.
As a whole, the MCU is all watchable and fun, with some movies being stronger than the other. When you're dealing with an 11 movie series, not all of them can be amazing winners.
