ALL the Beatles, OBVIOUSLY, and if you wish to hear them, the Sheffield Direct-to-Disc Lincoln Mayorga albums are excellent.
Classical, any Decca is usually OK, but specific orchestras and composers depend upon your personal taste.
I happen to like Linda Ronstadt and the Eagles, but many probably feel these are overdone. Ronstadt has a wide and varied catalog and a voice second to none, although she likes Bonnie Raitt, so take your pick.
I also like some quirky stuff like the genius of Harry Nilsson, but that's just me and, of course, "RCA records and tapes."
I don't know opera, but others probably do.
MOST important, enjoy the MUSIC! Some forget that this is what it is all about.
Cheers!