Encrypted disk image would be the best way to securely store things. As a comparison, I keep a 16gb flash drive with me at all times, and it has among other things, my password list. That information is in an encrypted dmg file, that I keep synced with a copy on my computer. On my computer, the password is in the keychain so it never bugs me when I want at my password list.
But with that flash drive in any other computer, I have to supply the password. That way I can have my cake and eat it too. (have my passwords on my flash drive with me, but not worry about if I lose it) And its minimally inconvenient. The only issue I deal with is updating a password on the flash drive to make sure it gets synced with my computer sometime shortly thereafter.
