"And by the way, if after reading this you still wish to use a traditional password manager, I suggest that you put your passwords into a plain text file and encrypt it with GPG or use Password Safe."

Having recently had some significant trouble with a lost online banking password, I've been thinking about keeping all my passwords in an encrypted file stored in various places (I don't like the idea of using a password manager, because it's difficult to move it across platforms). Is this sensible from a security POV? Which is the best encryption to use and is there a standard *nix tool for it?