@ Haxxy: Why do you say that "The last thing bitcoins need is a physical transfer medium"? Don't you think that a device able to be brought with you can be very useful and helps increasing the spreading speed of the currency?
The ideal transfer medium is the smartphone. It has Bluetooth and web connectivity, allowing phone-to-phone or phone-to-PC transactions, as well as wallet encryption and automatic backup. Also, eliminating the physical card helps people psychologically feel and understand that bitcoins are a step forward. Besides, one would be much more inclined to adopt Bitcoin if all it takes is downloading an app, rather than ordering a card.