According to a survey done by Google's AdMob, games are the number one use of most tablet computers out there, including Apple's own iPad and iPad 2. As you can see from the chart above, 84% of tablet owners play games on their devices, a use that's apparently ahead of even email checking, search, or newsreading and social networking. That's interesting -- when the iPad was first introduced, Steve sat on a couch and read email and news, but it turns out that once you get these things in people's hands, the number one thing they're doing is playing games.
Just like the iPhone, playing games are a big deal on these mobile devices, and they're also a big way Apple has been able to sell both apps and hardware.
Additionally, 38% of respondents say they use their tablets more than two hours a day, and 82% have been using their tablets at home. Anecdotally, I'll guess that these are still supplementary devices, though -- people are using their tablets while watching TV or otherwise engaging rather than using them directly. Only 28% of respondents say the tablet is their primary computer, but 43% say they do use the tablet more than a traditional PC. Interesting to see how usage patterns on tablets are really inserting themselves into an everyday work flow.