Like in Gmail 2.0, you can add colors to your folders in the Dashboard. You could also change ownership of documents or presentations (not yet spreadsheets). Check out the What's New page:
http://www.google.com/google-d-s/whatsnew.html

You can also change document ownership (only for documents and presentations though). I saw this in the source code last night but didn't realise they were actually going to launch it today! :-)

and a new Toolbar: http://blogoscoped.com/forum/127314.html

http://googledocs.blogspot.com/2008/03/new-toolbar-and-menus.html

Seem to be having some problems with Firefox 3B4 :-(
http://cheesemonger32.googlepages.com/ffprob.PNG

in Fx3b5pre it works fine, but the arrow looks also so strange

There are a couple products that displayed funny for me with Fx3b4. I ended up just uninstalling it and going back to Fx2.

It works OK (not perfect) for me with Fx 3b4, and oddly OK in IE8 (albeit a few UI issues exist).