Blender 2.61 is now out, and it features a new realtime renderer that takes advantage of GPU power.
Since blender imports almost anything, if you need a realtime solution, but can’t afford it, try blender, load up your model, and test lighting, materials, etc.
There are also extended groups of primitives such as 5 different pipe joints, complicated shapes such as dodecahedrons (and many more), bolts and much more. These have to be turned on in the Addons section.
(Open blender, hold Cntrl + Alt + U, and click the Addons tab. They are part of the Objects or Create sections. Email firstname.lastname@example.org if you have questions.)
Hope this is useful and helps you save a buck or two!