Most lead guitarists of metal and rock bands wear their guitars low because it "looks cool".... But you'll notice that whenever they have to play a hard part they get into what has been commonly called their "power stance"... Normally they'll hold the neck of the guitar up so that the fretboard is higher. That way they can play the fast runs easier... Zakk Wylde and Slash are both known for this. Just do what feels best to you... I wear mine right about in between.... So my belt buckle is about right in the middle of hte back of my guitar.... I do the "power stance" thing as well though... It makes some of those fast runs a lot easier to pull off... and it "looks cool".