The latest Pew Internet report tells us a good deal of information we already know about device ownership and penetration among US adults. Based on a Q3, 2010 telephone survey of roughly 3,000 US adults the chief value of the survey its demographic information and the historical tracking of the same questions and responses over time.
I've pulled out a few of the charts below. The first one shows the penetration and growth of various categories of devices during the past four years. The noteworthy data point here is the decline of the desktop PC.
At this point mobile phone ownership among adults is at or above 90%. According to Pew, it's 89% on average among US residents under age 65. Among those under 35 the numbers are 95% or more (if teens were to be included). Unfortunately Pew stubbornly doesn't seem to ask about feature phone vs. smartphone ownership.
There are roughly 238 million US adults according to the 2010 Census. If we extrapolate the Pew figures it means that just over 200 million US adults (using the 85% overall average) have mobile phones. However these figures are probably low.
CTIA puts the number (including teens) of wireless subscribers at 293 million. While it's true that some people have two phones (e.g., BlackBerry, iPhone) most people do not have multiple subscriptions.
The four major US wireless carriers report roughly 272 million subscribers according to their most recent filings (rounded):
The iPad/tablet findings are also interesting. There is a separate chart and question for eReaders like Kindle; these data don't include Kindle or other, comparable eReaders accordingly.
A major caveat here is that these figures don't include Q4 2010 (holiday buying). About 15 million iPads have been sold globally to date, a majority of which are still in the US.