I've been having a brilliant offline conversation with JoshB. He brought up an aspect of MS Surface Multi-touch Othodoxy that I just disagree with:
"My understanding of NUI was that you have fewer paths but the frequency of interaction is higher and more contextual relative to GUI."
I'm going to get heretical here and say that multitouch in existing kiosk applications (ATMs, Ticket kiosks, etc.) is a usability disaster waiting to happen.
In "single serving" applications, you want modeless interactions and a linear decision tree. If you are going to design a linear decision path and minimize interaction modes, why not go a step further and just do single point directed disclosure...like every ATM in christendom.
It cuts hardware costs in half and increases usability.