http://www.linuxlinks.com/article/20100201125214753/Geometry.htmlIn the field of mathematical software packages, applications such as Wolfram Research's Mathematica, and Maplesoft's Maple system instantly spring to mind. These are both highly popular, proprietary, commercial, integrated mathematical software environments. Other types of mathematical software packages generally receive much less publicity.
I quite like GeoGebra - its good fun to play with and a great teaching tool