Of the ones you mentioned, I honestly believe that LTC has the greatest upside in terms of multiple.
BTC of $5K by year end is reasonable...I also think $25K BTC a couple years from now is not out of the question.
I foresee LTC going up at least 10 fold from here. At some point, since I see LTC as the money, $500 per coin is reasonable.
So to use your analogy, if BTC is digital gold and LTC, as Lee wants, digital silver, then silver wins in terms of percent return.