Well, it's official - Longhorn is not coming out until 2006 - and when it does - it's going to be stripped of many of the features relating to then WinFS file system - the main component it was stealing from X's Tiger. That leaves a full year for Apple to refine and promote Tiger - a really golden opportunity to showcase a fully matured and feature rich OS against a no-show opponent. Additionally, you just know that what they at MS push out the door in '06 is going to be very riddled w/ issues.
I hope the folks at Apple are circling the wagons - and getting ready to hit this hard. I don't know that this opportunity will present itself again.