yes, surround mastering for movie and game audio are big. Isn’t that why PG put a video player in WL ? Detailed sample libraries are also another source of multichannel audio. You have mutiple mics setup > multiple channel audio files, think Superior Drummer or BFD. Lots of 3D audio formats store their files as multichannel and it would be great to have a quick way of editing/chopping these … etc…etc
Basically as @rat points out, there are an increasing number of formats and platforms for these. And we really need a way of dealing with these at the mastering stage.
Obviously you need a calibrated surround setup to get proper results, although bear in mind that the calibration between music/movie audio is not necessarily the same BUT if you are a musician/mixer, get started I WOULD try to hook it up to your domestic “dvd” playback system. Try doing a remix in cubase/nuendo using surround…you might get hooked