"Nearly 1 in 4 U.S. wireless subscribers could make mobile phones their primary telephone by 2009, a move driven less by cost and more by lifestyle, a market researcher said Tuesday. Fully 9.4 percent of the 193 million wireless subscribers today have made it their primary phone, In-Stat said. That percentage is expected to increase from 23 percent to 37 percent in 2009, when the number of wireless subscriber in the United States is expected to reach 240 million."
Wireless has to get a lot better, as this article points out, before I would make a total switch. The issue of needing the copper line for Internet access also needs to be addressed. Perhaps if we ever see Internet over the power lines more would switch.