I do think that the 3D market (oh snap) has the potential to explode over the coming years. There is a sense of inevitability about it now, rather than of it being a fad. People are very comfortable with watching 3D movies for the first time, and that will likely spread to sports events and possibly general entertainment programs. I assume thats the angle from which you're coming at this from?
It would perhaps be most suited to a 3D news site rather than products. I think the main potential is in the names targetting 3D products (TVs, screens) and services (subscriptions, promotions). It's hard to put a value on such a name right now, other than the ones really on topic (3dtelevisions.co.uk etc, which I saw here recently).
If you're coming at it from a different angle, as in a 'second life' type marketplace where people buy stuff in a 3D environment, then I think there's perhaps more value to the name as it's very much on topic. Perhaps most retail outlets will have such online stores in future, so I can see longterm value... as in, in 3-5 years time.