Release Date Order:
Iron Man
The Incredible Hulk
Iron Man 2
Thor
Captain America: The First Avenger
The Avengers
Iron Man 3
Thor: The Dark World
Captain America: The Winter Soldier
Guardians of the Galaxy
Avengers: Age of Ultron
Ant-Man
Captain America: Civil War
Doctor Strange
Guardians of the Galaxy Vol. 2
Spider-Man: Homecoming
Thor: Ragnarok
Black Panther
Avengers: Infinity War
Ant-Man and the Wasp
Captain Marvel
Avengers: Endgame
Of that lot I'd say my least favorite films are The Incredible Hulk, Iron Man 3, Thor & Thor: The Dark World. Felt like they didn't "find" the Thor character until Avengers, and then in Ragnarok they perfected him.
My favorites of the bunch so far are Iron Man, Guardians of the Galaxy, Infinity War
Still need to see Captain Marvel, but otherwise I'm up to speed.