I think, as a film, Winter Soldier may be the best put together. But from a pure action and enjoyment standpoint, I really love The Avengers.
I think that is just where I stand as well. Many of the movies had great moments, but these two stood above the rest to me for the exact reasons you stated.
For pure shits and giggles I love the two Deadpool movies best.
Marvel IP, but not technically MCU moves, at least not yet!
And I am excited to see what they do with the Fantastic 4, they've all been between disappointing to terrible so far, of course that is only my very subjective opinion.