G3DViewer is a 3D file viewer for GTK+ supporting a variety of file types:
   - 3D Studio (.3ds, .prj)
   - LightWave (.lw, .lwb, .lwo)
   - Alias Wavefront Maya (.obj)
   - Impulse TurboSilver / Imagine (.iob)
   - AutoCAD (.dxf)
   - Quake II Models (.md2)
   - Neutral File Format (.nff) new

Some of the features are:
   - Wireframe mode
   - Specular lighting (not really nice at the moment)
   - changable background color :)

WWW: http://madsworld.exhome.de/g3dviewer.html