There are no physical buttons on the front; all of the navigation controls are on the bottom of the screen and are virtual, meaning they'll always be at the bottom of the screen whether you're in portrait or landscape.
You can customise widgets by tapping a "plus" button in the upper right hand side of the screen. From there, you're given your choice of widgets to drag and drop wherever you want.
The browser lets you tab through and looks very much like a desktop experience. We even got a peak at how Gizmodo looks!
Gmail looks very clean and typically sparse:
On Google Maps, you can rotate and zoom and tilt in 3D. It's beautiful enough to get a few oohs and aaahs from the audience. We also got a quick look at pop-up notifcations, which show up unobtrusively at the bottom of the display.
Task switching: a left-hand pane lets you choose among a number of apps, and it looks simple and quick to bounce between programs.
YouTube now! Videos are presented as a 3D wall. It's pretty, it's smooth, it's an interface I'm looking forward to trying out for myself.
Googe Books are also presented as a 3D space, and it synchronises automatically with the cloud so that your purchases are kept in sync across devices. It's wireless and automatic.
The actual reading part looks a lot like iBooks, which is not a bad thing! Hard to innovate on letters against a white background.
And the front-facing camera! We got a quick look at Google Talk video chat, which may have been a tiny bit choppy. As you might expect, though, it's silky smooth in the official T-Mo demo video:
It was a just a quick runthrough, but there's enough here to be excited about. And if nothing else, it calls out just how un-tablet friendly Froyo has been.