I have three of his albums. He is a very diverse artist, so be sure you explore an album before buying it, as he has released some mainstream solo piano recordings as well as some excellent EM/ambient selections.
Of the three I have, I consider
like rain through my hands the best. Most of the music is minimal echoed piano against a backdrop of assorted ambient textures. One more active track reminds me of a song by Vangelis from the
Chariots of Fire soundtrack. But most of the CD is more introspective and subtle.
Aftet that, I'd recommend his classic spacemusic release
Nightscenes which has been re-mastered and had three more dynamic fusion-istic tracks added to the original release. This is an EM release, definitely, featuring lots of synths, some nice beats at times, echoed piano, and some EWI (think Kevin Braheny) as well. Stephen Hill featured it on Hearts of Space when it first came out (HOS was the label for the original issue as well).
Finally, I have a jazz fusion release of his I also like called
The Border of Dusk. If you like jazz fusion, you would probably like this as well.
The man always engineers and produces his CDs with great care and high quality. I think
like rain through my hands was one of the very best ambient releases the year it came out.
His website is pretty comprehensive
http://www.michaelwhalen.com