Google has just upped the ante by declaring its entry to the OS wars, of course to the chagrin of MSFT folks.  Regardless, it's always better to have options.

Does it matter if our favorite Windows applications won't run in it?  Maybe but I'll live.  Ars Technica's piece on the Chrome OS. 

Speaking of which, while searching for operating systems, I found this beautiful piece from Mr. Paul Hawken.  I suggest you read, too.