A 3D scatterplot made of 1300 punching bags (click picture for larger view) by artist Michael Kalish from Wired, with an impressive 2D marginal scatterplot of Muhammad Ali.
Not really statistical and not totally visual, but here is an interesting 3D representation of data. Using time, frequency, and volume this tone yields a 3D graphic in the form of a chair. Click on the link to designer Matthew Plummer Fernandez then click on sound/chair to hear the sound of a chair.