1 BTC vs 1 LTC valuation is not what you should be looking at, its mining revenue per hour. LTC pays twice as many coins and makes blocks 4 times faster. This graph on coinchooser is the one to look at, if the LTC % exceeds the BTC % then in my opinion LTC will have become the leading currency.
http://coinchoose.com/charts.phpMining revenue as a stat is dubious as miners chain hop to maximize revenue and coins routinely change position. The difference in profitability is merely an indicator of risk and the fact that miners are slow to react.
Try looking at value of money supply
Bitcoin $1,022,348,788 94.06%
Litecoin $56,641,732 5.21%
Namecoin $2,853,747 0.26%
PPCoin $2,592,646 0.24%
Novacoin $875,368 0.08%
Feathercoin $627,977 0.06%
Terracoin $364,711 0.03%
Devcoin $319,913 0.03%
Freicoin $218,006 0.02%
Yacoin $126,128 0.01%
Total $1,086,969,016
I only looked up the top ten because beyond that we are talking less than 0.1% per coin and it rapidly goes down to negigible valuations.
Another way of looking at it.
Bitcoin $1,022,348,788 94.06%
Litecoin $56,641,732 5.21%
Top 8 Altcoins $7,978,496 0.73%
Total $1,086,969,016