Just a quick rec (and let me second all the aforementioned recordings: Mwandishi, Emergency [I'm w/Skip and Steve on this one - absolutely essential - although I like McLaughlin's "Extrapolation" and "Where Fortune Smiles," as well], Lawrence of Newark, etc. - and, of course, MO's "Inner Mounting Flame" - but I'm surprised no one's mentioned Larry Coryell [with or without Eleventh House], Gateway, J-L Ponty...): Fourth Way Less heavy, perhaps, than all the other groups but they represent another side of the fusion coin. On that (lighter) tack, I'd also recommend Gary Burton's work w/Coryell, Bob Moses, as well as Keith Jarrett's early albums w/Jerry Hahn, etc. And I don't know whether anyone besides me is willing to call Oregon fusion but their albums are certainly worth checking out. (And what about the "rock" side of this equation? Brand X, anyone? 'Course, talk about dated production...)