Though I'm inclined to look to events particular and present, nothing opera-related in 2007 struck near as deep as the death of Luciano Pavarotti. Yet of course the event, as significant (if weirdly under-marked) as it was, released him into the date-unbound present of history: in the future it will always be some time around the 1970s for him, and the particular year he died may not be much remembered.
In fact, one might speculate, perhaps there's some child lately born whose appearance will be the true operatic event of 2007? But such a thing, of course, was not in my experience of the year.
To be honest, the most memorable Met performance I saw may have been at Carnegie Hall, when violinist Christian Tetzlaff gave a most Beethovenian performance of Beethoven's concerto. (Whether or not it's evident, I loved "classical" concert music long before I loved opera.)
In the house? 2007 was the year I realized how great an opera Jenůfa (well, "Její pastorkyň" if you like) is. I'd seen and heard it before, of course, and in some excellent renditions, but it was not until everything went right for Jiri Bělohlávek and his superlative cast that I discovered that it is not just a very good less-performed opera but one of the cultural landmarks of the last century: not just dramatic and terrible but ultimately triumphant, and throughout as indomitably alive and varicolored as its ever-present river. Many other works have seemed weak echoes of Janacek's masterpiece since. (Oddly enough, about a week after the last of these Met Jenufas I saw Cilea's L'Arlesiana, which actually does tell a similar, if gender-inverted, story... Though it ends in death, not reconciliation, and is so much the more sonically and emotionally monochromatic for it.)
2007 was also the year I was reminded how great Mozart's Figaro is, by a terrific and well-matched cast. But "remind" may not be the right word -- even mention of Figaro can remind my brain, but the joy and high spirits in these performances recalled Mozart to my limbs, heart, and blood.
Oh yes, and I saw maybe the greatest assumption of Lucia ever. But I've bracketed that in my head until March.