A while ago I got a Nexus S and one reason was that it came with NFC. I am not sure I want to use it for wallet type application but there are other things to do with it. There are a lot of great apps in the Android Market that make use of NFC but the coolest one I found is Touchanote (website; app). This app works in conjunction with Evernote (app) and it basically can "store shortcuts to your notes on NFC tags to be able to access your content when and where you need it with the touch of your mobile phone" (quote from the website). The company also sells NFC tags for the lowest prices I found on the web (outside of wholesale) and they also send you a free tag just to try it out if you send them your idea of how you plan to use it. I have a free tag coming my way soon but I couldn't wait so I bought a couple tags and tried it out.
I have a few possible applications in mind but the one that I ended up doing was a very simple one yet very useful (for me, at least). I created a Shopping list note in Evernote that I can edit from my phone and also on the web interface, used Touchanote to write the link to this note on a tag, put the tag in my wallet and when I get to the store I tap the phone to the wallet (which is still in my pocket) and voilĂ : the shopping list pops up on my phone. How cool is that?!
Thanks a lot, Touchanote for such a cool and useful app!