Save your keyring by encrypting it separately, using a long but easy-to-remember passphrase. I use openssl and AES.
A more thoroughgoing solution is to give every file you want to preserve an unguessable ID, and use that as the passphrase for that document. Use a hash (SHA-1, typically) of the ID as the "name" of the document (i.e. the subject line when you email it to your gmail account). Make sure that the hash you use for the ID is different from the hash used to turn your passphrase into a key! (openssl uses MD5, so that's OK). A convenient hack for generating unguessable IDs is to use a hash of the file's content. Hash-based version-control systems like git make this trivial. (If you use this trick, you need to encrypt the list of IDs using a passphrase you can remember!)