I've owned and subsequently broke a pair of 3d lcd shutter glasses at one point, before nvidia really started pushing the support for it and released their own nvidia 3d glasses.
the feeling of immersion was incredible. it was like being in a game in a way that's difficult to describe. the 3d is perfect, and at the time it worked on pretty much any game that didn't use the doom3 engine, and even with that, only certain things didn't work, like looking through glass, was 2d.
there's a product called the novint falcon, http://www.youtube.com/watch?v=mW70elK9Yrs&feature=fvw, that provides haptic feedback, and there are different attachments (so you can hold a gun, for instance, instead of a...thing...search youtube if you're curious for more) and greater 1st party support for more games now, but this video gives an idea of what it does.
obviously the xbox 360 project natal will be a pc peripheral eventually, as well
can you imagine a vr headset, where you don't use a monitor (old and probably obsolete example: http://www.3dvisor.com/faqs.php) where each eye is given it's own image so you see in true 3d, plus headtracking so you just look around with your head to look around, plus this novint falcon thing,
and if you can squeeze some kind of natal stuff in there for your other hand, even better
If you've never tried even crappy vr, with crappy graphics (tried it at a local arcade once) where you wear a headset, and when you move your head, you actually look around
it's so amazing. it's like being in another world, and even if it's a blocky polygonal world, it's still unlike anything else.
I'm so glad to see more and more technology move in this direction for consumer consumption. I can't wait until full immersion like this is fully supported by everything, because it's already possible to have a pretty awesome experience with what's out now. speaking of which, if my tax return is what it was last year, I think I'm gonna be buying most of the aforementioned.