I plan on making some simple addons for it, whenever they let people get their hands dirty coding. I've not as of yet seen any API documentation, so I'm awaiting that.
I hope, considering the robust Skyrim modability, they have a pretty mod-able UI. We'll have to wait and see.
I can already think of dozens of addons the UI might need for many people who are used to the more traditional MMO setup.
Here's how the basic UI looks, for reference:
http://www.youtube.com/watch?v=hfpYnehJ5TE
This is the latest Dev Play session, posted by Zenimax.