[chx]

For me, the ideal solution would be a cross platform password manager software which stores your encrypted vault ... somewhere -- I hate the "cloud" word but let's use it -- and then has a small display which the password manager on your phone can read and decrypt the vault with it. It's just a few hundred (thousand at most) bits that you need to carry across, not a big deal. For desktop / laptop / charging, it needs to be USB pluggable. Physical form factor approximately like https://www.adafruit.com/product/2690 this or http://www.ebay.com/itm/Mini-4GB-LCD-Screen-Display-MP3-Musi... this.

The problem currently is a) most sites want passwords b) I do not want to mess with cables c) NFC is not ubiquitous.