Like BriceKolob said, mid-knee cap or at the bottom of the knee is most comfortable for me too. When I can I have my kilts made a bit longer I do, otherwise I have to wear the off the peg a bit lower than I would prefer, but just don't feel comfortable sharing that much of myself.

Maybe its a delayed reaction to the ridiculously short, short pants that we wore in the 70's.

Cheers,

Marshal Moroni