As for The Topic of the Day...
Operettas - I've never been a fan of the G&S canon, but I think that has to do more with my experience with some diehard Savoyards rather than the quality of the material.
If you already know all the words and all the traditional blocking, then why do you feel the need to rehearse it all over and over and over again for weeks at a time? Otherwise,
The Merry Widow comes to mind.
And then there is
Die Fledermaus which seems to get cross-categorized under operetta and opera in some circles.
As for operas...
Among the usual suspects:
La Bohème - I do have a fondness for the classic recording with Victoria de los Angeles and Jussi Bjoerling conducted by Sir Thomas Beecham on Angel/EMI. However, a voice teacher I used to play for gave me a copy of Maria Callas' recording which I also find satisfying (surprisingly so). -Callas only recorded the role, she never performed it on stage.
Among the not so usual suspects - and most of them are in English too!:
Susannah by Carlisle Floyd - Since I went to school in Richmond, the two big soprano arias from this opera were practically de riguer for the women in the department. I like the recording conducted by Kent Nagano, but, alas, I'm not too fond of Cheryl Studer's portrayal of the title character. -I've just never liked the way her voice records.
The Rake's Progress by Stravinsky - Besides the wonderful "No word from Tom" for Anne and "The world is so wide" for Tom, there is some sublime music in the closing moments of the opera. -And from Stravinsky no less.
I know many people who covet the recording conducted by the composer, but I really do prefer the Nagano set with Dawn Upshaw, Jerry Hadley, Samuel Ramey and Grace Bumbry.
Powder Her Face by Thomas Adès - Some people love this chamber opera, some people hate it. I love it. A great mix of styles, and the story is based on the real-life downfall of Margaret, Duchess of Argyll in the 1950s. And the composer is actually three years younger than I am! The set is still available on EMI at full-price, but I've seen it in many a bargain bin.