This list was a lot harder to put together than I thought. The last decade has been a golden age for comic book/superhero fans. My top 10, starting with my favourite:
1. Avengers: Endgame
2. Avengers: Infinity War
I see these more as one interconnected story, and it has to represent the crowning achievement of the genre, the kind of spectacle that would have been unimaginable just 10 years ago. So many great moments and every character gets a chance to shine. Thanos is the best villain since Heath Ledger's Joker and one of the greatest in cinematic history, right up there with Darth Vader. Endgame edges out Infinity War for me because Cap is my favourite Avenger. And speaking of which...
3. Captain America: The Winter Soldier
4. Captain America: The First Avenger
Tough to decide between these two, but Winter Soldier has the better action scenes and the "man out of time" element. I enjoy Cap's friendship with Sam Wilson and his interaction with Black Widow and Nick Fury. Still love First Avenger though, which has real heart and nostalgic thrills to spare. Joe Johnston deserves a lot of credit for successfully adapting an "old-fashioned" character that many at the time thought would never be accepted by a modern audience.
5. Black Panther
Although Cap edges out Black Panther because the former is my favourite MCU character, if I'm being honest with myself Black Panther is probably the objectively better film. Social relevance, amazing cast and worldbuilding with Wakanda, real drama, and the best MCU villain outside of Thanos. Great soundtrack too.
6. The Avengers
The feeling I got seeing these characters onscreen together was indescribable and I always have to give kudos to Joss Whedon for pulling this off. Still a classic.
7. Logan
Easily my favourite of the X-Men movies. I love how different it is from any other comic book movie, its standalone quality as a neo-Western, great performances from Hugh Jackman and Patrick Stewart, and Laura/X-23 is one of those rare movie kids that are actually really enjoyable to watch onscreen.
8. Wonder Woman
Gal Gadot is to Wonder Woman as Christopher Reeve is to Superman. Her romance with Chris Pine is my favourite in any comic book movie of the decade. I enjoy the World War I setting and of course the No Man's Land battle sequence is excellent.
9. Aquaman
One of the most consistently enjoyable popcorn movie experiences I've ever had. There's just so much movie here, and I love it. It throws everything but the kitchen sink at you, and it's totally cheesy, but great fun. Love the cast, the visuals, the music.
10. Thor: Ragnarok
Was thinking about Deadpool in this space, but I ultimately have to give it to Ragnarok just for the action scenes set to "Immigrant Song". Perfect marriage of music and character. Just a really funny and enjoyable movie.
Shockingly, my favourite superhero, Superman, did not make the cut, even though Man of Steel and to a lesser extent the Ultimate Edition of Batman v Superman were probably my most frequently watched superhero movies of the decade. There's still a lot to love in both, but unfortunately, there are just too many flaws for either of them to make it into the Top 10.
