I think there will always be a steady stream of new coins, but when the dust settles BTC and LTC will be the only ones left standing with good value.
There may be a couple of others that offer something of real value. Stablecoin or Anoncoin offer a higher degree of anonymity, Namecoin messaging, etc., but there's no doubt that every idiot with a "-coin" name is out there changing a few lines of code and then dumping another junk coin without knowing how to run the coin.
A coin has to offer something beyond being not-bitcoin or not-litecoin. Whatever, pump and dump, pump and dump.
Freedom, you've got to love it!