@ChrisDee: You sír have no clue. I myself studied guitar at the german version of GIT. I had famous Metal teachers as well as Jazz teachers. I play in several Bands: A Jazz band, a metal band and a cover band. So I know and love both styles....Granted there is metal that is simple in terms of music theory, but there is much more to metal than kirk hammet solos. Metal, especially Progressive Metal has grown to one of the most complex music forms. Just listen to John Petrucci, Steve Vai, Van Halen, George Lynch....They are many metal guitarists that play at least as complex in terms of harmony/music theory than any famous jazz guitarist. And using jamiroquai as an example is especially wrong. While I like them, they definately make very simple music in comparison to many metal Bands like Dream Theater, the aforementioned guitar players and even death metal bands like Death, Meshugga, etc....
I have nothing against people preffering other musical styles, but I hate people discriminating other musical styles than their own without knowing what they are talking about.....Listen to some good metal or Jazz/Fusion bands and learn about some bands that make challenging/complex music and not easy-listening style like jamiroquai.....