If you're really struggling for lists I'll throw a hasty fave five in off the top of my head, the bonus here is my relative lack of knowledge before the comic movie boom really happened so here's a snapshot of my unknowing self.
1. The Incredibles
It's just so dang fun, it really nails that interesting dynamic of your standard family that are also pretty super.
2. The Dark Knight
My backstory for this movie is going in genuinely with the mindset that 60's Adam West Batman was how Batman was supposed to be, yep, I hadn't seen Begins either, I'd basically only gone because one of my friends didn't have anyone else to go with at the time
The phrase "on the edge of your seat" is a classic cliche but I'n all seriousness my butt was getting perilously close to the threaded precipice towards the endgame, this wasn't just a film I enjoyed the heck out of, it was when I finally realised "oooooh, the campy show my dad always insisted to me was the real deal was in fact the outlier". I should've known better than to trust a man who almost unconditionally hates everything after the sixties.
3. Captain America: The Winter Soldier
I was very surprised by the First Avenger, as a Brit I expected patriotic shield man to be aggressively bland. Instead I got this lovably earnest string bean who lives the dream all short skinny chumps like me aspire for, getting a dosage of fix all super serum.
Still Cap lacked some oomph in his fight scenes, that was before Winter Soldier delivered on showing what a Super Soldier should be pulling off in combat, it seems a lot of the best marvel movies are the ones that can sneak in pulling off being a different genre of movie with superheroes in tow.
4. X2
I'm struggling to actually recall why I dig this one, maybe it's because I've watched so many X-Men related films now and this still trumps them to me, DoFP comes close (I've always been a Beast mark so he's immediate bonus points) but when it comes down to it I get more of a Patrick Stewart and Ian McKellan fix over here.
5. Iron Man
A film that can be almost entirely carried by how much its lead fits the part, I actually saw 2 first ( my first MCU movie even) and thought it was the drizzling shits so I put off the origin story until 3 was about to come out, turns out I should've gone back sooner.
Still don't like 2 at all though
An inherent problem I've sound with most superhero movies especially as of late is that I enjoy them a lot on the first run but they lack punch on the second, the above are ones that survived the rewatch.
If I were to throw in five more on a whim...
Batman Begins, Guardians of the Galaxy, Deadpool, Big Hero Six (heavily for Baymax, whatta guy!) and The Avengers (for sheer scope)