the "cheap" way i have been using is max's wire frame material on a duplicate of my geom over a shaded version.

That works OK, as long as you add a Push modifier to the wireframe model. I like renders where the wireframe is understated, say 33% solid on top of the shaded model. I also like it sometimes when the shaded model is flatshaded instead of smooth, but I think that depends on what you want to show.

There is a materail plugin that does it.

snotmonsters EdgeMap

http://www.bytegeistsoftware.com/prod01.htm

ah many thanks.