Immersion
Surround sound is a tricky thing. In theory great surround is simple: A decent surround amplifier, multiple, correctly placed speakers and a room with proper acoustics. In practice this is a very hard goal to achieve, unless you happen to have a room to spare.
Yamaha may have come up with the next best thing: The Yamaha YSP-1 Digital Sound Projector. It's basically a device capable of directing sound waves precisely enough to generate surround sound by reflecting sound off the walls in a room. Seems like an interesting compromise if you are going for surround but can't really go for the full blown N-speaker deal. (Room-wise that is, this thing ain't exactly cheap.)
The voices in my head are all around me...
While virtual surround in a room is interesting, headphone-based surround is more so. The thing is, that we only have two "native" channels, our ears. In theory, with sophisticated DSP processing, it should be possible to create surround which sounds just like the real thing. This could do wonders for things like playing computer games when the kids are asleep. If the hype proves real, the Creative X-Fi may be just the thing...