My Top 10:
1. Iron Man (2008)
The first MCU film, and probably still the best.
2. The Avengers (2012)
It made history, and it still stands up as a great film (even if Cap's costume doesn't hold up at all

). Loki is probably still the best MCU villain (well, more like reluctant/anti-hero nowadays, but you get what I mean).
3. Avengers: Endgame (2019)
A great finale to Phase 1, with some of the most epic moments in the whole MCU. I think everyone who saw it will remember its biggest moments.
4. Avengers: Infinity War (2018)
Even as just the first part of a two part story it did a great job and works as just a very good movie, and seeing the heroes actually lose was a great cliffhanger.
5. Guardians of the Galaxy Vol. 2 (2017)
I legitimately love this film, its technically #5 on my list but its very close to the others. The story and cast feel like they work even better here then in the first one, and overall its just a great movie from beginning to end.
6. Captain America: The Winter Soldier (2014)
Chris Evans as Captain America is great, and this was his best solo film. Different from other MCU films that came before, but still fits the MCU well.
7. Captain America: Civil War (2016)
As one of the few people who actually enjoys the comic event I still really enjoyed this film. Even if it barely resembles the comic, it works with a similar concept (heroes being hunted by the government), and it is definitely still Cap's movie, even with so many other characters involved in the story.
8. Thor: Ragnarok (2017)
Easily the best thor movie. We don't have to deal with the idiot humans, and the humor/action are great. Hulk/Bruce Banner are also standout characters, and who doesn't love Loki, Hela and the Grandmaster? It loses a bit by the film not taking some moments seriously enough (killing off the Warrior's 3 and Thor never really acknowledging it or really the death of Asgard in general is one of the few big flaws of the film), but its such an enjoyable experience that I can forgive its faults.
9. Black Panther (2018)
T'Challa is great, Killmonger is an interesting villain, and getting the kind of world we get with Wakanda is something that feels very unique and different.
10. Captain America: The First Avenger (2011)
A very good movie that hits the tone its going for perfectly. Great action, and it just feels like a Captain America movie.