@Ian2: a word of warning... I tried the FEZ Panda II with the FEZ Touch. All in all it's a decent playground, but there are a few issues you may want to consider.
- Memory is scarce. As in really, really scarce. Tens of KB are enough to write a pretty complex program in C#, but if you plan on having an UI you won't be able to fit resources in there. Plan on having a micro SD on hand.
- Transferring stuff to the screen is slow. If you try to use a font larger than just a few pixels, you will get flickering. It might be possible to write a better driver for the parallel interface, but that will require a professional ARM compiler as the free ones tend to bloat the firmware and further reduce the amount of memory you can play with.
- The touch screen is nothing to write home about. Aside of the odd spike that it's relatively easy to filter, you also get quite some lag if you happen to be writing to the screen. Workable, but don't expect to emulate a modern touch UI, it doesn't even come close.
- The GHI assemblies are less than great. Lots of underscores (it's silly, I know, but it really irks me), and poor integration with the .NET MF. Again, it's workable, just not very clean. And the documentation just sucks.
On the plus side: the Arduino compatibility is good. Lots of hardware you can buy and use, with the only drawback that you may have to write a driver or, at least, a .NET layer to make the device usable.
Bottom line: it's a decent deal to experiment with the technology. But if you plan to do anything more serious (and you need an UI), find a better device.