And on the brain implant thing, wouldnt the decent solution be just to trip your brains happy switch permanently? but like stainless said, scary thoughts...
So basically feeding you with some hard "stuff"
"Rendering" holograms is basically possible, you can create displays able to render holograms (although you really need tiny pixels, in terms of showing the light wave pattern), and place them on all the walls and floor of room. If you would have enough computation power to actually render the hologram (note that it'd be petabytes of data to process for single frame, maybe even more), you could render 3D hologram inside that room. And you wouldn't need any glasses for that.
The problem is, first of all, money - the LCDs or anything else is not able to render holograms, you need smaller "crystals", single pixel should have just some nanometers, not hundreds of micrometers (thats several orders smaller). Next thing, processing power. As you use several orders of magnitude smaller pixels, you need several orders of magnitude more computation power to actually compute what should be drawed and draw it.
The second problem is "touching the hologram". This is generally huge problem. First of all you'd need to define what is touching suface - touching surface e.g. colliding with it - your finger is composed of matter (particles), once the particles are approaching some object (F.e. desk), the electromagentic forces grows as distance gets smaller (unless you're so close at atomic level, they are basically zero), once the particles get really close, this force grows (almost towards infnity). And you can't pass your finger through the desk (because you can't overcome this force).
Overcoming this force is possible, F.e. inside Tokamak devices, Sun or Thermo-Nuclear explosion (e.g. Fusion bomb), using huge temperatures and pressure, you can perform nuclear fusion (e.g. overcoming this force and fusing particles together), but thats not the subject of "touching the hologram". Basically you would need to be able to somehow "simulate" this force without the actual matter. The problem is, that we basically don't know how to create electromagnetic force without some emittor (maybe some theoretical force field could do this).
Then we would just need some advanced epic-level artifical intelligence, so we could create Doc from Star Trek: Voyager. :ph34r: