The videos don't tell us a whole lot more than we already knew, but they do flesh out the iPad's actual use better than all the arguments over capability in the world. And some of these videos, especially Numbers, Pages, YouTube, and Keynote, haven't seen much action so far--nobody really knew all that much about how they'd work.
The videos are, as always, simple and beautiful, and focus on the features. They don't go particularly in-depth (you won't hear any musing on the New York Times' embrace of HTML5, for instance, but you will see Times video working well, a stark contrast to the blue question cube Steve Jobs summoned at the device's debut). And you will see exactly how, for example, you can lock the screen rotation or adjust brightness in the iBooks app. Check out Apple's site for ten others (and in better quality).