Probably The Avengers, just as an all-around solid movie. However I think The Hunger Games could be a runner up.
Prometheus and The Dark Knight Rises I think are flawed films however you slice it, even though they are probably the most 'rewarding' blockbusters this summer. And I think one could start a discussion comparing just these two films in the ways in which they are flawed. To me the most obvious difference is that The Dark Knight Rises can't pretend to not already have all of its cards on the table. Whereas Prometheus can still come back smirking (when's the sequel again?) and try to -retroactively- claim that some of its holes were already covered. Although its most obvious shortcomings such as lack of empathy for many of its characters would still remain.
I can't share people's disappointment with The Amazing Spider-Man because for me it still improved on two of the three prior films in its franchise. But I also don't think it is an Avengers or a Hunger Games. Nor is it as rewarding as Prometheus or The Dark Knight Rises. Even though I'll dare say I think it is a better movie than the latter.