Geospatial Modeling Environment (GME) grew out of Hawth’s Tools, a collection of tools that provided welcome and easy functionality with an ArcGIS-interoperable toolbar. ┬áIt has always been optimal for environmental and ecological work, but its functionality can be applied to many other application areas. Now a stand-along package, with all of the original bits and more. It has software dependencies on both ArcGIS and R; see the download page for more information.