10. Peter Grimes (Benjamin Britten, 1945)
Britten was the most celebrated British composer of the 20th century and arguably the best since Henry Purcell (17th century). Grimes was his first and best opera, a Verdian essay on a socially outcast fisherman.
*if you liked this you might like Billy Budd
9. Tosca (Giacomo Puccini, 1990)
Puccini wrote the best Italian Opera of the 19th century. That's not to say he wrote the most authentic Italian opera, as that accolade is more properly laid upon Verdi. However, as far as opera has mutated into a modern subgenre that typifies the trappings of 'opera' as a modernist would understand it Puccini is the exemplar. Doubt of this was vaporised when Marc Forster used the climatic close of the first Act to underscore a particularly melodramatic sequence in the centre of his Bond blockbuster, Quantum of Solace (2008). This bit, in fact:
*if you liked this you might like La Boheme
8. Così fan tutte ('They're all like that', WA Mozart, 1790)
It was banned/performed in bits in the 19th century because people thought it was subversive. They were right. It starts as sweet, innocent fun and ends in horror.
*if you liked this you might like The Marriage of Figaro
7. Der Rosenkavalier ('The Knight of the Rose', Richard Strauss, 1911)
As discussed. Actually, it's a bit of a cheat this as Der Rosenkavalier is overlong, certainly compared to the great, dramatically punchy predecessor masterpieces Salome and Elektra. However, it does have Elysian music, a post-Wagnerian flood of glory that doesn't subside until you're a wreck, as I re-discovered five hours ago.
*if you liked this you might like Ariadne auf Naxos
6. Jenůfa (Leoš Janáček, 1904)
What? say those of you who've never heard of Janáček... and those who have. Well, if a test of a great opera composer is to have completed at least three masterpieces in the genre, then he makes the grade. Jenůfa is the most violent, passionate, tragic and cathartic of his output.
*if you liked this you might like Katya Kabanova
5. Otello (Giuseppe Verdi, 1887)
Really, it's possible to complete this list using only the operas of Giuseppe Verdi. To paraphrase the former editor of Opera Magazine, Rodney Milnes, to dismiss Verdi is to misunderstand the nature of opera. Verdi also had a thing about Shakespeare which meant that the plots were ace too and his setting of Otello has all the quintessence of opera: love, jealousy, Machiavellian deceit and melody.
*if you liked this you might like Rigoletto
4. Wozzeck (Alban Berg, 1925)
The only truly 20th century opera on this list, with all the themes and lush lyricism of what had gone before but with the sounds and sensibility of what was to come.
*if you liked this you might like Lulu
3. Carmen (Georges Bizet, 1875)
Sex and death with great tunes. People use it for ringtones. 'nuff said.
*if you liked this you might like Cavalleria Rusticana
2. Don Giovanni (WA Mozart, 1787)
Don Giovanni is a rapist, a violent tyrant and a liar. He's also the hero of Mozart's best opera and so we can't help but love him even when he's being dragged into hell.
*if you liked this you might like The Magic Flute
1. Tristan und Isolde (Tristan and Isolde, Richard Wagner, 1856)
It's rather long and the principals spend five minutes discussing the word 'and' in the second act. Yet it's arguably the greatest piece of music ever written, let alone opera, and if you're really tuned into it it hurts.
*if you liked this you might like Die Walküre
Consequently, I would be prepared to say that the greatest three operas ever written are Tristan, Don Giovanni and Carmen. I'd like to make a further assertion, also from this list, namely that the three greatest 20th century operas are Wozzeck, Jenůfa and Peter Grimes (Der Rosenkavalier was completed in 1911 but it is firmly in the tradition of its previous century).
I am aware that the earliest opera on this list is Don Giovanni, completed 1787, and that the basically knowledgeable will be scratching their head, mouthing 'no Monteverdi?'... to which I can only plead ignorance/a self-evident limit of 10, and counter with 'hey, no Handel!'.