@johnkzin and @gerbick

Well the current Zunes allow 3rd party "apps" (mostly games so far) but there is no App store. The whole development process is in C#/XNA and you need to load it via MS VS. However thats probably going to change when the Zune HD hits. I believe that Zune marketplace is going to gain an App store as well. This is basically a guarantee.

@eiffel
The HD refers both to the device's ability to play 720p videos (albiet downsized) on the device screen itself and also the ability to output those videos in full 720p resolution over HDMI. It also refers to the device's build in HD radio reciever.

I admit I am a Zune fanboy and have a lot of high hopes for this device. I just hope HD doesn't turn out to stand for Huge Disappointment.

I hope the Zune HD is a great success too. Anything to loosen Apple's grip on the mp3 market.