Who gives a shit about scars on the knees? I have loads of scaring from skating there nad rock shorts all the same. Shorts which come 3/4 are unflattering to the line of your body, making you look stumpier than you are if you're a short guy. Tall guys can pull of longer shorts, but any longer than the knee caps and they look weird. Tim, go for some plain, neutral coloured chino shorts which hit at or just above the knee caps.