I also believe that the current US standard for mobile phones is non-extensible so there's going to be a shake up if the US is to join Europe and Japan in the next generation. I think when you start throwing the term wireless around you have to divide it into two camps. On-site wireless and roaming wireless. I think on-site wireless will be huge as more people get a chance to enjoy the convenience of unattached connectivity. No more worrying about whether there's an open drop in the conference room, and better, you can sit on the couch watching the Giants kick butt in the playoff game while surfing.
Mobile wireless is a tougher sell beyond the geek community.
I have been glad to have net access on my phone now and then, but sometimes go weeks and weeks without using it. I suspect most people are not even using it that frequently. I wouldn't differentiate between on and off site. My money is on Bluetooth as the next Gorilla. It's hard to be objective when you're self categorizing.