I think he was using the wifi version because his didn't have the extra black plastic portion along the top. And I don't THINK there were any signal bars or AT&T in the status bar. Also, maps still work with the wifi version, but instead you get the wifi location technology instead of the GPS. Of course, this is useless while on the road since you won't get map data.
Personally, I'm getting the wifi version. I have an iPhone with a data plan that provides maps, and suffices for the little surfing I need to do while away from a wifi hotspot. Now to decide on the size...
At least I have an extra month to decide!