Thelonious Monk. Granted, I only have a compilation and the Monk. album, along with a couple of stray songs, so I can't really pick an album to recommend. But you absolutely cannot go wrong with Monk. Here's a couple of my favorite tunes:
Well You Needn't
Monk's piano technique, while highly unorthodox, is also extremely sophisticated in an almost primitive way. When it comes to improvisation, Monk had it down. If you haven't heard Monk yet, then listen now.