I've written a new article covering smart property, that is, physical items in the real world whose ownership is controlled by the Bitcoin block chain. You can find it here:
https://en.bitcoin.it/wiki/Smart_PropertyI give cars, phones and house locks as examples of things which can be traded or used as collateral in a cryptographically mediated way. Feedback welcome as always.
After my London stay, hotel room locks come to mind also

EDIT: I'm trying to come up with more "immediate" (not that Mikes examples are unrealistic, they are just a bit far away for now) examples, something we can do now, rather than after having the automobile industry embrace bitcoin, which might take another year or 1.5 ;->.
Maybe access to gaming platforms is feasable, or access to servers? Could we make a pam module?