Some jazz and classical solo piano recordings worth checking out:
Art Tatum Solo (7 CDs)
Lara Downes - Exile's Cafe, Goldberg Variations
Seong-Jin Cho - Chopin and Debussy albums
Ingrid Fliter - Chopin
Thelonius Monk - Solo Monk
Leon Fleisher - Two Hands
Alfred Brendel - Beethoven and Schubert Sonatas
Glenn Gould - Bach 2&3 part inventions, well tempered clavier, violin sonatas, 1981 Goldberg Variations, etc.
John Medeski - A Different Time