It's a wider topic than I'd realised!
The hardware is still quite young, and there's plenty of mileage left in it, but it's funny that we've not yet seen a developer tackle something like an RTS yet. The only problem is the size of the screen - zooming in would work on something nice and slow like a point-and-clicker, but I couldn't imagine zooming into a warzone to pick out a few units!
Maybe a music-mixing game would work, too? Although handheld games consoles and the clubbing scene aren't the most obvious partners!