I've been monitoring 3DTop's progress for the last few years. While I'm impressed that they continue to work on it, it seems like their program doesn't actually accomplishing anything. The key bit is that 3DTop doesn't actually make the windows 3D, they merely create some 3D background. I fail to see the point of having 3D in any part of the environment unless the whole environment is going to be 3D.

In reference to the other link, "When to use 3D", I'd like to suggest that 3D has usefulness that extends beyond the situations they listed. Most of the time people think of rather vulgar 3D environments, ala the wierd Unix system in Jurassic Park. I suggest that 3D could be used successfully to augment an otherwise 2D interface. Microsoft already did this (sort of) when they made all their buttons appear to be 3D, or in maintaining a sort order of windows to provide the sensation that the windows are actually behind each other. I believe that many 3D techiques could be very useful if used in similiar ways, providing the user with 3D references that they could mentally key off of.