Microsoft is currently developing three other operating systems aside from Vista.
They plan to split it up, so that there is a Windows for the average consumer and a Windows for companies. This does not mean that there are going to different versions as we know it from Vista (Home, Business, Ultimate, etc), it does mean that they are building completely different systems with completely different intentions.

 

Currently there are only speculations about Windows Midori, but they assume it is going to be a OS for business applications and huge networks of PC’s that can access those appliactions via the web.

 

 

Aside from that there will of course be a Windows 7 that is expected to be released in 2010. According to my source they are simultaneously working on Windows 8, which is a bit strange. However I hope that they take a look at some competing products before they develop another Vista without too many innovations.