A microsoft led standard, Informationcards, are making real headway in the identity sector. Novell is leading a linux and OS X implementation of an 'identity selector'.
If what identifies you is now too long to remember or type, usb keydrive support will be needed for cafe setups. Or maybe someone will implement an online information card repository that you access with.... user/pass. ha.
My next rails project will need to support user/pass, openid, and information cards.