Stephen Samuel's Journal: MS Expat: Linux is 50 man-years away from world domination.

After 10 years at Microsoft with less than "10 minutes with any Open Source code till I left Microsoft-which is actually very typical for MS employees.", this expat left Microsoft and spent a year using Linux (mostly Umbutu). It was a bit of a shock. To be precise, he "had an epiphany that Linux on the desktop is 99.999% ready to go. Linux is lean, stable, polished and extremely rich. All of the pieces needed for world domination on the desktop are there."

His back of the envelope calculation is that Linux is about 10,000 bugs away from being fully world-domination ready -- or about 50 man-years -- and some of those bugs are due to lack of support from device manufacturers.