Microsoft has shipped copies of it's next Operating System, Windows 8 to OEM partners via Microsoft Connect. There's no release date as of yet, but I'm sure details will come sooner than later.
There are very few details about Windows 8 at this time. Among the rumors floating around are tighter integration with Microsofts cloud service Windows Live as well as a System Restore called "History Vault".
Windows 7 is rock solid and hasn't caused me any problems thus far so I can't wait to get my hands on Windows 8.