I guess I'll just back up copies. I read that some people just throw back up on sites like dropbox ... is that secure enough?
Maybe (depends on the security of your wallet passphrase and/or security of dropbox) however even if it is secure it isn't cold storage.
https://www.bitaddress.org/(keys are generated client side but for higher security you can download and save a copy of the webpage and run it offline)
Use paper wallet option. You can also encrypt the private key by checking the BIP38 option but be sure you don't forget the passphrase.
Print out multiple copies, put the copies in secure locations, transfer coins from your online/hot wallet to the address on the cold storage paper wallet.
You now have a offline cold storage of your coins. Keep your "spending money" online and the bulk of your wealth offline on paper. A