OK, it seems like others have been mostly suggesting popular jazz (if any jazz at all), so I thought you might enjoy some lesser known artists (as well as some known artists that have thus far gone unmentioned). A quick list of some of my favorites that have already been mentioned includes John Coltrane, Miles Davis, Thelonius Monk, and the Mahavishnu Orchestra (and individual members of the orchestra, such as John McLaughlin). Other great artists (and individual musicians) inculde Tower of Power, Stanton Moore (and his band, Galactic), Joshua Redman, Wes Montgomery, Art Blakey, Billy Cobham, Art Pepper, Brian Bromberg, Medeski Martin & Wood, John Scofield, Karizma, Vinnie Coliauta, Sean Jones, Brand X, Cameron Mizell, Dennis Chambers, Herbie Hancock, Liquid Soul, Dave Weckl, Christian Scott, and Christian McBride. Keep in mind that some of these may be funkier than others, and others may be more fusion than jazz. However, I would highly recommend any of these numerous artists or groups to any person looking to get into jazz and its various forms.