Louis Armstrong.
Also, most anything by Charles Mingus, Thelonius Monk, Eric Dolphy, Art Blakey and the Jazz Messengers, Ornette Coleman (Art Of The Improvisers is great), Charlie Parker, Dizzie Gillespie, John Coltrane ('60- '64 is my favorite period, especially for learning about how radical bop could be: pre-free-kowt stuff), Duke Ellington has lots of stuff where the arrangements are beyond genious... so many fucking layers. Damn.