3D Warehouse content can now be downloaded directly into Arc2Earth, the ArcGIS to KML exporter, where you can use it as a replacement for marker icons. The killer feature is this: Arc2Earth can restyle the content according to the markers’s attributes. Writes the developer, Brian Flood, on his blog:

A2E can use this [attribute] information to “re-style” the model in part or in whole. In this regard, the models become more dynamic since they can be styled to display all different sorts of data. Likewise, the models can be scaled and rotated by fixed or attribute defined values. So style, size, orientation and clearly location are all dynamically applied during the export.

Plenty of examples over on Brian’s blog.