Die Frau ohne Schatten
This opera is generally, though not necessarily universally, considered a strong contender for Strauss' greatest opera. It certainly got Von Hofmannsthal's best, if most symbol-laden, libretto. I prefer Karl Böhm's 1977 recording (third act cuts and all) from Vienna. Indeed, his cast was a bit over-the-hill (though James King had sung Parsifal at Bayreuth only six years earlier, and was about to do so again for Kubelik), and Böhm's later years were not his best; however, he understood Strauss. A conductor like Georg Solti was very good in his repertoire, but Die Frau ohne Schatten is far from Das Rheingold. Furthermore, by the time Solti cut Die Frau, he was a better celebrity than a conductor, not that he was that universally great to begin with (his near-perfect Ring aside). Böhm still had a few years left in 1977, and he had yet to cut his very slow, very thoughtful, and oddly moving Beethoven 9th. He was a musician to the end, unlike Solti and Von Karajan, who seemed less interested in solid music-making and more interested in being seen with the Pope or in a red fedora. Respectively, in reverse order.
I like Die Frau, though much of Strauss is still a mystery to me. The Vier letzte Lieder, Ariadne, and now this seem to have their charms, rivaling Wagner and Mahler for my attentions.