If you have been using KML in your GIS work flow then the new features of ArcView9.3 will have you jumping up and down. You will no longer have to jump through multiple steps to get your data in to a kml file. This allows you to share your data with non GIS people and have them use a piece of software that they probably are very familiar with. The best use I have found is allowing clients to preview project progress without having to spend time and resources installing unfamilar software for your clients. Check out this video on what Arc View 9.3 can now do with kml.