The Perfect Skirt Length
Crewsing Thru My 50's has a great guide to determining your personal perfect skirt length, depending on whether (and by how much) you are short-shinned or long-shinned. I measured as 16.5" upper leg and 14.5" lower leg, a 2" difference, which means that my ideal skirt length is 1 inch above my knee.
I have no intention of giving up or hemming all of my skirts and shorts that don't fall perfectly proportionate, though. While 1 inch above the knee is perfectly modest for me, I also like midi-length skirts and much shorter shorts (3-5" inseam). This does explain why that one pair of too-short capris that hit just below my knee was so awkward-looking.