The interfaces for 3D CAD software keep improving. They have to, because working in 3D is not natural on computers. There are two approaches: hardware and/or software. Companies like Logitech hope you'll like their hardware; companies like Autodesk hope to make progress on the software side.
Autodesk is showing a new 3D interface in the forthcoming DWF Design Review software. Its purpose is to let non-CAD users easily interact with 3D models -- rotated, sliced, and exploded. Scott Shepard has a blog entry that details the different kinds of translucent wheels that will be available: click on a segment of a wheel to pan, rotate, zoom, walk, rewind, and so on.
Interesting concept, and probably more amenable to non-CAD users than training on a SpaceTraveller. Cheaper too, in that the cheapest 3dConnexion device is still $59 more than the free DesignReview. I trust the new interface works better than the seven-year-old 3dOrbit command in AutoCAD. If successful, I'd expect to see the wheels rolling into AutoCAD 2009.