There are 16 featured tablet apps in the market. Search for HD, THD or tablet, and you'll find considerably more. I'm working on one of them.
Google could stand to refine the UI for finding tablet apps, though in fairness to them, showing off 16 good ones on launch week was probably a reasonable move.
(Written on a tablet-adapted HN reader that isn't one of the 16, on a Xoom.)
The relevance is that the apps are what provide the UI.
For the iPad there are 65,000 of them customized to utilize the full screen. For the Xoom, there are 16 customized for the full screen, and the rest are literally just blown up phone apps, many of which don't even rescale properly.