One of the reasons I game on a 5.1 surround set is it helps me compensate for my horrible vision and terrible field of view.
RenderB, via Twitter
Even just stereo panning makes a huge difference, but surround sound rather than stereo allows for much more effective identification again of where sounds are coming from, particularly important for people with impaired vision who rely on sound cues either as reinforcement or as a sole means of understanding gameplay.
Best practice example: War Thunder
Best practice example: Diablo 3