So many great recordings. If you absolutely love the sound of the cello, you can wallow in it via Villalobos' "Bachianas Brasilieras No. 1," written for a cello ensemble. Delightful Latinate melodies to boot.
The best recording of the Bach Cello Suites is, regrettably, not in modern sound. But the set by Pablo Casals is a jaw-dropper, with Slava Rostropovich's EMI set not too far behind.
The Beethoven piano/cello sonatas, featuring Richter and Rostropovich are also amazing but again, not demonstration-quality sonics, which has always been fine by me, but others might feel differently about such matters.
Cello is difficult, though. Some like Yo Yo Ma, others find his sound kinda wimpy, and want some meat to the playing, as you get from Casals and Rostropovich. Pierre Fournier is a nice midway point, and as Rex44 notes, Kim Kashkashian is indeed a winner. Also on ECM, so the sound quality is extraordinary.