Which is your favorite opera?

Question:

Which is your favorite opera?

Best Answer - Chosen by Asker: Ack, so hard to narrow it down to one..
I think "Le Nozze di Figaro" by Mozart is just pure musical perfection; and it has a good mix of comedy and more serious issues (love, social classes, traditions in high society)...
But my sentimental favourite is "Hansel und Gretel" by Humperdinck- I think it's by far the most underrated opera- the music in it is just heavenly and the story is so sweet...
Another underrated is "Dialogues of the Carmelites" by Poulenc which I just find so incredibly moving-especially the final scene