What's the right tablet operating system?

Yesterday, everyone who watched the Academy Awards in the U.S. saw the first TV commercial for the iPad. Today, Adobe and HP released a video showing Adobe Flash and Air running on HP's Windows 7-based tablet. Tablets haven't been this popular since Moses, but I have a sense that we may be going in the wrong direction.

This is turning into a "Goldilocks" situation: Scaling up the iPhone operating system for the iPad is too little, but scaling down Windows 7 for the HP Slate is too much. Both approaches have a big benefit, in that the hundreds of thousands of applications that work on the two respective operating systems will run on their respective tablets--just not well. In the case of the iPad, scaling up iPhone applications for the bigger screen will lead to some clumsy user interface compromises. As for Windows 7, it's going to be very tempting for software developers to add a flimsy tablet layer to their existing applications and call them tablet applications, again with severely compromised user interfaces.

So, what's my crazy tablet OS suggestion? A few weeks ago, I bought a Zune HD. (Let the snickering commence.) The Zune HD user interface is the basis for Windows Phone 7 Series, and it actually works very well with touch input. (The keyboard sucks, but I think that cramming an onscreen keyboard into the Zune HD took things a little too far.) The visual and kinesthetic metaphors in the Zune HD are worlds better than layering a touch interface onto Windows 7.

Microsoft's Courier concept may tie into this as well, but Courier is very heavily dependent on its two-screen design; many of its user interface metaphors wouldn't map well into a single-screen tablet. I'd be very excited to see a Zune HD-like user interface on a tablet, and I think that it would give Apple a serious run for its money.