At the moment the only use for NFC tags for this phone is for your own purposes. So you could stick one near your bed...and in your car and things like that to automate daily tasks.
I am sure in the future you will be able to use it to pay in places like Starbucks or McDonalds, but its not quite there yet.
I think there are also plans to embed NFC tags in posters in train stations etc so you can wave your phone at it, and get some publicity on your phone.
I had some Xperia S tags so I tested the One X with them just to make sure NFC was working.