Yeah, I use the Ernie Ball straps too - cheap and effective, and lo-o-o-o-ng :D
Back in the days of Mr Page, I used hang my guitars down at mid-thigh length.
But, as I get older, I feel, stood in front of the mirror, that middle aged gits seem to look kind of odd dressed in their Blue Harbour M&S clothes with a guitar slung around the kneecaps :lol:
I find that I tend to sling different guitars at different heights. Eg a strat generally feels and looks more comfortable lower than a tele. But it also depends on the type of music I'm playing at the time.
When it comes down to it though, one has to remember what an electric geetar is all about - it's just a pen1s-extension really. So no matter what height I have the guitar, the line of the neck always bisects the general area of my crotch :lol: (kinda difficult to do with the Jimmy Page height!!)