Kodi/XBMC now runs on a great variety of operating systems and hardware.
It supports ARM and Intel processors, Windows, OS X, and several shades of Linux.
Plex is a fork of the original XBMC open source project that first became available in 2009.
Originally finding traction on the Mac as a media server, it has since been extended to Windows and Linux.
Perhaps the biggest contender is Kodi, which is the new name of the open source XBMC (Xbox Media Center).
XBMC started as a hack of the original Xbox, which was essentially a locked-down, Intel-based PC in its first incarnation.
With all the ports available, Kodi can run on old hardware (with some limitations on performance), like the first generation Apple TV, and newer boxes like Amazon Fire TV and the current Apple TV.
So if WMC is a dead platform, where do you go from here?
WMC has always had competition, on both Windows and other platforms.
Microsoft recently announced that after a dozen years, it would no longer include support for Windows Media Center (WMC) in the upcoming Windows 10.
WMC was novel when introduced as a special edition of Windows XP in 2002.
It has a clean 10 foot interface and works out of the box with remote controls designed for Windows Media Center.