Vista is only out the door and speculation on its replacement has already started. Sure enough, MS is already working on it and seeking feedback. But the speculation has lead to a comment from Microsoft. So here it is, straight from the horses’s mouth (Kevin Kutz, Director, Windows Client):
"The launch of Windows Vista was an incredibly exciting moment for our customers and partners around the world, and the company is focused on the value Windows Vista will bring to people today. We are not giving official guidance to the public yet about the next version of Windows, other than that we’re working on it. When we are ready, we will provide updates.”