The tipping point, as noted by the team over at DesktopLinux.com:
Opinion — Sometimes, several unrelated changes come to a head at the same time, with a result no one could have predicted. The PC market is at such a tipping point right now and the result will be millions of Linux-powered PCs in users’ hands.
The first change was the continued maturation of desktop Linux. Today, no one can argue with a straight face that people can’t get their work done on Linux-powered PCs. Ubuntu, PCLinuxOS, MEPIS, OpenSUSE, Xandros, Linspire Mint, the list goes on and on of desktop Linuxes that PC owner can use without knowing a thing about Linux’s technical side. People can argue that Vista or Mac OS X is better, but when Michael Dell runs Ubuntu Linux on one of his own home systems, it can’t be said that Linux isn’t a real choice for anyone’s desktop.
What else do they have to say?