To confirm though, once I have a paper wallet with ltc deposited, I can just leave it there. Then when I want to sell, I will have to download something like litecoin-qt? I can't just make a deposit to an exchange like btc-e or cryptsy? I would have to take my private key, import it to litecoin-qt and then I can move it to an exchange? I just have a laptop so the idea of downloading all these big files is unappealing.
Yes, you got it right!
If your wallet is passphrase protected, you will have to unlock the wallet before you issue the "importprivkey" command. You can do this with the following command in the "Console":
walletpassphrase "yourPassPhrase" ###
Where ### is the number of sec. the wallet should be unlocked
importprivkey yourPrivateKey
Where yourPrivateKey is the private key that you want to import.
The client freeze for a few minutes, this is normal since it has to scan the entire blockchain.
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I don't know any other options for litecoin, you have to investigate that.
I know for bitcoin that you can import a privatekey into blockchain online wallet, or mycilium can also load a key, actually you can use the webcam, its pretty cool. Mt.Gox also had a "redeem private key" function before he died.
I will recommend that you try loading a paperwallet with 0.001 LTC and try to redeem them again, so you have some experience and know what you are doing the day you need to redeem your saving.
Edit: Maybe else someone knows if there is a litecoin online-wallet that can redeem privatekeys, simular to blockchain-wallet?