Windows now supports all media formats that QuickTime used to enable, Windows plays just about any mainstream format without the need to install anything, just out of the box.
For me, the only reason I have QuickTime installed and will continue to keep it installed, is that it is required by three of my favorite games, Myst (original), Riven and Silent Hunter II.
I don't care about security risks, since I won't open any QuickTime specific files and I don't have the QT browser plugin. Just the most basic stuff so those games can run.