Transit agencies in the Greater Toronto Area have a Presto fare card which the NFC reader picks up, but it can't read any of the data on the card (I presume all of the data is encrypted). The Toronto Transit Commission has been reluctant to adopt Presto, because they wanted a more "future-proof" technology that could accommodate credit cards and cell phones (and because TTC management is notoriously stubborn), but there have been noises about Presto adopting those modes of payment in the future.
The Brampton, Ontario library system uses NFC for checking out books. Each book has an NFC sticker in it that is read by checkout machines, and the Nexus S can read it as well, but all you get is the library's unique ID number for the book. (I desperately want a Brampton Library app that scans the book and gives you info on due dates, pending holds, etc.)
Curiously, my tap-to-pay Visa card can not be read by my phone, but I've assumed it uses something other than NFC (like RFID maybe?).