Sometimes, I wish I could make an excerpts CD of parts from various Grétry operas and give it to people. For example, the finale to Act 1 of La caravane du Caire, or the very interesting opening to Richard Coeur-de-lion... it starts out extremely dark and heavy, but then blurs into a pastoral, cheerful choral scene. There's no standalone overture to that one, it's really a little jarring and strange, but it's really fantastic.
I also sometimes wish that no CD of Dittersdorf's symphonies had ever come out, since it gets people to avoid his operas (and chamber music, as well). I like a few of his symphonies okay, but despite the large number of them, I think it was in his operas and chamber music that he shined. Apparently, Joseph Haydn was a bit fan of his Il Barone di Rocca Antica, and I like it quite a bit myself... I not only have it on CD, but in a DVD as well. I hesitate to recommend the DVD, since the choreography is utterly embarrassing as far as I'm concerned. However, other than that, the performance is really, really good (it's almost worth the price alone just to see those period instruments in action before the stage). There are several really star parts here, including the finales to both acts, which show a great skill for combining complexity and subtlety that would probably surprise the many Dittersdorf-bashers out there.
By the way, I also have that recording of Martín y Soler's Una cosa rara. As a whole package, this is one of my absolute favourite operas. I have to admit when I bought it, it was blind and mostly due to the references in Wolfgang Mozart's Don Giovanni. Boy, what a lucky stab in the dark this was! I've got it back out now, I almost forgot how amazing it was from start to finish. In my opinion, I'm thinking Mozart might have had a hard time picking which music to borrow for his own opera, since there's a seriously large amount of very catch material here.
I wonder how many complete operas I have from the Classical Era. I'm just looking through my collection, and geez. I have 11 complete operas by Cimarosa alone (not to mention 3 separate recordings of Il matrimonio segreto, and 13 complete operas by Paisiello, and more (such as 3 complete operas by the relatively obscure Piccini). I used to have a serious interest in Classical period Italian opera, and seeing this discussion has suddenly revived a bit of an itch in me. I know what I'll probably be listening to a lot of the next few weeks!