Ethan has written a great mini-essay on Andrew Hill worthy of those he wrote on Ornette Coleman (also, don't miss his public display of devotion towards Hill). In it, he highlights some unlikely spots: Grassroots and Pax. The title track of the former reveals Hill's sarcasm (check out the way the minimal-funk piano solo slips in and out of time). "Eris," on the latter album, bursts with wild energy.
Hill's quieter side is also present on "Erato," a hypnotic little trio piece on which Joe Chambers's brushwork ably suspends time. Ben Allison's evanescent sextet version of "Erato" can be found on his great album Buzz.