The writing is on the wall. Despite a major push to sell the much-maligned Windows Vista, customers aren't buying. Nearly two years after Vista's release, Windows XP remains the standard desktop OS in business, and Microsoft has extended its availability three times (currently to August 2009) due to customer demand. Microsoft itself forecasts just 2 percent growth in Vista sales in early 2009, after lackluster sales in 2008.

If Windows is a dead end, what's next?