To rehash the tired old quote, Bitcoin is like gold, Litecoin is like silver. In theory when all coins are mined Bitcoin will be used for larger transactions like buying a house or a really (really, really) nice car, Litecoin will have more coins minted in circulation so it can take care of smaller transactions.
How valid is that. Is there any reason why bitcoin cannot be subdivided into infintely smaller increments. It would just take a naming convention to make that simple. I mean it's hard to state a price as .0000000000001 btc but if that increment had a name it would be simple.
Seems like litecoin is just simply a different currency.