If you look at what is most profitable to mine in real time, some of the other scrypt based currencies seem to come out on top.  Litecoin is definitely an early leader but because of the number of people mining it, the profitability is dropping.  It wouldn't take much of a price swing to make another coin the best option in terms of return on your mining investment.

http://www.coinchoose.com/ has a great comparison chart for people looking to choose an alt coin to mine.