I would like to gather everyone's knowledge to create a list of touch screen friendly applications (for tablet PC). I see many nice widgets/applications on Android or iOS that were created with touch UI in mind. For example, several of news readers, and ebook readers, not to mention the famous Angry bird game :P
Besides the standalone application, I see a lot of potential to create a touch friendly applications with the latest HTML5 technology. For example http://html5.labs.ap.org/
I see great potential how people may interact with tablet PC with touch or pen, but I don't know much application that's touch/pen friendly. When I searched online, many drawing programs showed up, but I feel there are many other use, too.