There was an announcement on the XNA blog that there would be support for Zune games in the next release of the XNA SDK later this year. I think that is pretty cool! That is hardly why I purchased a Zune but it is always fun when hardware you already own is able to do more things.
There is, however, a huge tactile difference between the Zune 80 and Zune 30 and I am wonder if that will effect the playability of the games on the original models.
Disclaimer The opinions expressed herein are my own personal opinions and do not represent my employer's view in any way.