Yes, definitely, I agree. Italian and German composers are the world's greatest, when it comes to both the opera and the classical music in general. I believe that there are several works which you simply must listen to - such as Rigoletto, La Traviata and Nabucco, all of which were written by Verdi (of course, there are many more, but these three are my personal favourites). And who hasn't heard about Vivaldi or Puccini? There's certainly a reason why they're so well-known - their splendid music enchants. Curiously enough, throughout history, while people liked listening to opera, they had a certain distaste towards opera singers - they were considered... almost as inferior. This sounds a little like hypocrisy, doesn't it?