Credit Card, Coupon, and Reward Coupon. These are the three items that are thus far available in the Google Wallet system that you'll be able to use when checking in at stores, purchasing items like what Google showed off at the May 26th event in NYC, a pair of shorts from American Eagle. The system was further detailed from start to finish: look up the shorts at home, find a coupon, transfer the coupon to your phone the same way you'd transfer an app via the Android Market, and bring the phone to the store to tap. All you've got to do is sign!
In the same vein, receipts will be passed electronically, loyalty cards will be included in your Google Wallet, and additional fun item will be included in the wallet in the future. This is all what Google is calling Single Tap. The next fantastical product of this event via NFC was a tap-to-grab item via a poster. All they had to do was project an image to the wall with the correct symbol, and poof! You've got your brand new coupon. This of course will fall more under the Google Offers category.
Very exciting things going on with Google and their new NFC system.