Motorola has an interesting evaluation setup for their 16-bit S12E128 MCU. The main board has the MCU, LEDs, RS232 & RS485 drivers, the voltage regulator and a BDM port for debug/programming. The breakout every pin on the micro using 2 large headers, one on either side of the board. They also supply addon cards (which you can plug onto the headers) for:
- Prototyping space
- Ethernet connectivity
- Lots of buttons and LEDs
- Addon external RAM
You can plug in what you want to test and use the other pins for GPIO. If you don't need the external RAM (the MCU has 4k of internal RAM), then you can use those pins for other stuff.
Other people can create add-on boards to meet a specific target audience. Which is great for you if all you're trying to do it spread awareness of the MCU.
If you ruin one prototyping board, you just need to go out and get yourself (or make one yourself). No need to spend a stiff sum on the entire board. I feel this would promote creativity :).
For my applications, I would rather communicate with the board using an addon RS232 card (with necessary isolation) than use the built in USB port. This way if I made a mistake grounding the different parts of my system, I do not end up with paper-weight for a computer.
I am not so sure that the RS232 port will go away entirely except on the really low cost PCs. Even MS, who removed RS232 support in .NET 1.x has reinstated it in .NET 2.0.