Microsoft stopped launching yet another new version of windows because the upgrade ratio dropped off to the point it became embarrassing.
Have no (or plenty of) fear MS is working on new versions but is finding the technology hard going, however lack of demand, especially for Office upgrades is a major issue for them.
XP Server edition R2 soon then Longhorn (renamed Vista) 2006/7 to replace XP client but much scaled down from original plans. Longhorn R2 2007/8.
Major changes: new user interface, Vector graphics, improved search and security features and a lot of techi stuff.
Source: Gartner Group presentation Tue 8th Nov, Cannes France.
More on thread I just got my 196 and see no reason to regret that decision, colour on a 296 would be nice but not for the cost of 10 hours flying!