The latest build of the client operating system is richer and more stable, but it will require heavy-duty hardware.
When it ships, probably late in 2006, Longhorn will feature dramatically redesigned graphics (Avalon), storage (WinFS) and communication (Indigo) subsystems, as well as a new driver model---all of which are intended to contribute to a client operating system that's significantly more stable, more useful and easier to develop for than Windows is today.
Read more: eWeek.