I listen to a lot of Ornette Coleman, and am a big fan of his "harmolodic" approach to improvisation [basically that harmony, melody and rhythm play equal parts in driving the music, none at the expense of others]. According to James "Blood" Ulmer, one of the splendid guitarists to play with Ornette, one of the ways he achieved "harmolody" was to view the guitar as having only one string, and treating the six as six parts of one string. he achieved this in part by tuning all 6 strings to the same note. i have been playing in "harmolodic d" and let me tell you something, it opens up a whole new world of improv possibility, and the tone is out of this world. try it.