I had several responses to my query about software that could help me
represent new houses or subdivisions in 3 dimensional form with topography,
buildings and landscaping.

3D Analyst for ArcView appears able to do much of what I want, but
cannot represent 3d landscaping. SiteBuilder 3D (MultiGen-Paradigme
web sites www.multigen-paradigm.com and
www.sitebuilder3d.com)is an add-on to 3D Analyst and improves it
somehow, but I'm not yet sure how (or why to pay the extra money.)
Earthviewer (http://www.earthviewer.com/index.html)
looks very promising. World Construction Set
( http://www.3dnature.com/ )looks very interesting.
Neither seems to capitalize on my ArcView skills
as much as I'd like. ERDAS' Imagine and Virtual GIS
(www.erdas.com) are a package that link to ESRI products
or their output (such as shape files) so they might be a
good fit for me, but appear to be designed for
much larger scale projects (towns, miles-long flybys)
than I'm interested in. E&S Rapidsite (www.es-rapidsite.com)
appears to be in the same vein.

One problem for me is that my hardware is not up to snuff
for this type of work. Looks like you need a 1 ghz CPU,
OpenGL video card (Hercules Prophet II with 64 mb of
video ram or the Intense 3D Wildcat 4110 Pro for example),
20-30 gb of fast hard drive space seems to be the
recommended hardware standard. I can't even run the
evaluation copies of this software without a video card
upgrade!

Thanks to all who responded.

Jeff