I am in a mixed mood about this. On one hand, it means that we don't get a Microsoft tax in the form of Windows XP SE. On the other hand, it does mean that more advanced features due in Longhorn will instead be pushed back to Blackcomb, which I don't think we will see for years.
Its probably all academic anyway: any roadmaps or release schedules that Microsoft ever seems to release seem to be complete and utter bunkum. The truth is, you'd better just wait and see.