Chrome OS looks like... Chrome! (Shocking.) Looks like those TechCrunch screenshot leaks turned out to be real.
Chrome OS has "panels" -- small persistent windows. Good UI alternative to dealing only with tabs.
ALL your data on Chrome OS lives in the cloud. Showing a book-reading usage scenario. Browser windows can pull out like Exposé in OS X.


Google: "We want Chrome OS to feel more like a television than a computer. Just push a button and it's on." Uses custom PC firmware.
Video Explaining Chrome OS
Chrome OS won't be out until probably this time next year. (Unless you get and compile the open source starting today!)