I love exploring open GIS datasets with QGIS. It's incredible what this tool can do and I keep discovering new features or plugins all the time, which keeps it interesting. The amount of publicly available GIS data combined with tools like QGIS and PostGIS can be a big time saver. I don't work in the space, but occasionally run into problems requiring some form of support for geospatial data. Need a list of US cities and postal codes along with their respective coordinates? Easy. Find the dataset, import into QGIS, export to PostGIS. Done.