For those who don't know, or maybe don't listen to Xbox Live's Major Nelson (www.majornelson.com) The NXE (New xbox experience AKA the new dashboard) will be coming to your xbox November the 19th.
Quick things: -
You will be able to browse xbox.com select demos, themes etc for downloads and when you get home and turn on ya xbox it'll start all those downloads for you.
Avatar's which are like wii characters, will be added for you to customize
You'll be able to install any xbox game to your hard drive, however you will need the disk in the tray, just so it knows you still own it.
8-voice chat party.
That's pretty much it off the top of my head, sadly we won't get netflix!