Looking through the gallery, you will notice that Chromium OS really is just a Chrome browser with a new Settings menu.There actually seem to be less features than when Lee last had a look -- gone is the Picasa integration, and Gmail lost its cool chat manager. The 'slideshow tab' is neat, though, and the 'docked' media player should be popular (you can't drag it away from the bottom of the screen, though).
This is the external, public version of the operating system though. There's every chance that the internal, commercial version -- Chrome OS -- might look different. Google has said on numerous occasions that the internal version is very similar, though, so the final version may really look just like this.