Clifford Curzon, Menahem Pressler, Murray Perahia, "Solomon" Cutner, Vladimir Ashkenazy, Dinu Lipatti.
Curzon: buy them all. Solomon's Beethoven recordings are nice. Lipatti: Chopin Waltzes; Ashkenazy has some nice Schuber sonata and Chopin prelude recording. Same for Perahia. Solo recording by Pressler are hard to find; most are with Beaux Arts Trio. I've heard him live in solo recital and its the best I've ever heard in person. I guess I will also throw in older recordings of Daniel Barenboim playing Mozart Sonatas (I have them on LP).