Windows next version code named "Fiji"
Windows Vista still not relesed for the home users ( Business users editions only available now ) Microsoft is working now on the next version of the current Vista.
The new version code named "Fiji" will be relese around late 2008, some resources says that this won't be a major relese but will only be kind of Vista R2.
"Fiji" is an island in the south pacific ocean you can read more about "Fiji" the island here, and the Windows here.