If you're more of a rock type and are looking to get initiated in jazz, I wouldn't recommend Coltrane. Coltrane is, among others, the absolute essence of jazz. But if you are the uninitiated, his music may seem pretty boring. I was one of them. I couldn't listen to Coltrane for a long time. If you're looking to get fully into the jazz experience, my recommendation would be Miles Davis.
I think a good introductory example to jazz would be Stanley Clarke. Very nice mixture of rock n' roll with jazzy tunes. If you want the music to be more of a hard rock type, check out Tribal Tech and Vital Tech Tone, they add distortion to the guitar, and it may sound a-lá Primus sometimes. If you're looking for even heavier stuff, there was a 1993 album by a death metal band called Pestilence, the album is called Spheres; they were very influenced by Chick Corea (synth and pianist), and although the music is more death metal than jazz, the tunes themselves are very jazzy.
There are also several jazz fusion bands and artists out there. There is one called the New York Jazz-Ska Ensemble, which I like a lot. Herbie Hancock is also very influential on new era music, especially electronic. Us3's 1993 hit Flip Fantasia took the tune out of Hancock's Canteloupe Island. LTJ Bukem also uses Hancock a lot. Tropical/Cuban Jazz is also very good, if you enjoy that type of music. There's also a great band (not sure if they're still around) called Bela Fleck and the Flecktones. They have a nice mix of jazz with their own style. Bela himself plays the banjo and his bassist is Victor Wooten, arguably the best bassist out there right now. Wooten is a strong recommendation for bassists as well as Marcus Miller. Matter of fact, there is a song played by both Wooten and Miller, called Miller Time.
In general, I'd recommend to check out most of the Blue Note Records artists. If you're ever in New York City, drop by Birdland and just enjoy the music. I had the luck of doing that once and it's quite an experience. When going to a jazz concert you really notice why the best musicians usually lead into Jazz.
Ceiling_fan: Your guitarist recommendations are really good. I personally like Wes Montgomery and John Scofield a lot. But you seem to have left out one of the best jazz guitarists: Pat Metheny. And to a lesser extent, Lee Rittenour (aka Captain Fingers).
James2097: Ruben Gonzalez is excellent. I have a few of his CDs. If pianists are your thing, you may want to check out Michel Camilo and Claude Bolling. Oh, and the piano virtuoso, protege of Chick Corea: Hiromi Uehara... I saw her live this year and it's very impressive, especially since she can play the piano and the synth at the same time!
, Herbie Hancock, Bill Evans (harmonically the most beautiful IMO), John Coltrane, Wynton Marsalis, Miles Davis, Pat Methany, Anatholi Bulkin (Awesome newish guitar dude)..
I admit though, It does make the ride to school quite relaxing.
