Windows 7 has finally taken over Windows XP in worldwide usage shares

Kudos to Mac which is able to retain the 7% market share if not growing (this does not include iOS though). 

Windows 7 overtakes Windows XP global share

October’s statistics show Windows 7’s global marketshare stands at just over 41 percent, while Windows XP holds a hair’s breadth away from 40 percent.

In between the two, Windows Vista — long believed to be one of Microsoft’s biggest mistakes in the operating system race — dipped below 11 percent. Apple’s Mac OS X remained steady, but rising slightly at nearly 7 percent.