I would like to be able to add a song to a playlist while listening to it on my Zune. For instance, if I'm listening to my Zune and think "this would be a great workout song", I'd like to be able to do that on the Zune as it strikes me.
Similarly, it would be great to be able to apply custom defined tags to songs. I see that the rating system has gone from 5 stars to a range of 3 hearts. Although I agree that 5 isn't always necessary, being able to distinguish as (1) remove, (2) indifferent, (3) like, and (4) REALLY love would be great. This is an example where being able to have a custom tag to apply and categorize music while on the Zune would be great. With the thousands of songs on my Zune, especially through Zune Pass, I use the Zune to review and categorize my music on the go (who has time to sit down and just listen to music for the sake of rating). Given this, the Zune HAS to become a smart device that enables users on the go to record categorization, preferences, etc.
Thanks for moving the device forward. It's exciting what's happening with this product!