I like a lot of the bebop and cool/modal/free jazz from the 50s to 60s era, stuff like Miles Davis, Dave Brubeck, John Coltrane, Thelonious Monk, Oscar Peterson etc. Lately though, I've been more into modern jazz by bands like Polar Bear, Fulborn Teversham, Acoustic Ladyland and Led Bib as well as a bunch of solo musicians whose names I can't remember.
I like all sorts of instrumentation in my jazz. Sometimes I'll want to listen to some upbeat piano jazz or free trumpet/saxophone improvisation, other times nothing beats the mood of bass-heavy jazz. In modern avant-garde jazz, even electronics can be used quite effectively.