I don't know, but 3D domains are like what HDTV domains. Follow what bmugford says if you think you can hold it and hopping that the 3D industry will boom in the next couple of years then probably you can sell it up to high $XXX depending on the demand of the 3D industry.
But if you think the 3D industry will not be a big industry for the next couple of years then just drop it.
As of now, $RegFee
Have fun!
Aloofkid