Des Knaben Wunderhorn -- On Vanguard Everyman Classics. Sung by Maureen Forrester and Heinz Rehfuss. Orchestra of the Vienna Festival. Maybe my favorite record on my shelf, regardless of genre.
Symphony No. 1, conducted by Bruno Walter. Columbia Symphony Orch. On Columbia Odyssey.
Symphony No. 3, conducted by Jascha Horenstein on Unicorn. Also released on Nonesuch. The Nonesuch is not as good a pressing but the tonal balance is better.
Symphony No. 4. Concertgebouw Orchestra, conducted by Bernard Haitink. Fourth Movement sung by Elly Ameling. On Philips. My first exposure to Gustav Mahler. I heard it on the radio when I was a teen and was instantly a Mahler fan.