I manage a couple dozen ArcSDE databases, which means for each of these I have connections as a database owner, data owner, and publisher. My list can easy include 100 different connections. I also need to maintain a few dozen links to ArcGIS Servers, both ones I manage and ones I consume.
It would be awesome if I could set up subfolders in ArcCatalog under the Database Connections and GIS Servers to make it easier to locate these connections. They map to a folder in my profile so it shouldn't be hard to manage subfolders as well!