I was going to suggest Ahmad Jamal as well. VERY underrated jazz pianist.

Add another plug for Horace Silver, IMO the all-time piano master of hard bop. Look for the stuff that he recorded with Art Blakey, as well as his Blue Note recordings from around the early-50s thru the mid-60s (Finger Poppin', Blowin' The Blues Away, Song For My Father, 6 Pieces of Silver, etc.)

Two other jazz pianists you should try on for size are Kenny Drew and Sonny Clark.