I haven’t posted too much on Desktop GIS, but I was thinking today I’d look at what extensions and scripts I use every day that are not ESRI products. The biggest one lately has been the TerraServer Download for ArcGIS 9.0 which has been a big help to getting up to date imagery on sites around the country. We have quite a good collection of DOQQs over the past few years, but they aren’t as up to date as the TerraServer imagery is. The other utility for ArcGIS I’ve been using is the Geodatabase Diagrammer. If you have Microsoft Visio, there is no easier way to diagram the elements of a Geodatabase. Lastly I have been using the Batch Define Projection Python script practically every day. I wish one could just highlight all the layers in ArcCatalog and just right click and define the projection, but you can’t. This script is the next best thing.