Quantum GIS

Quantum GIS (QGIS) is a user friendly Open Source Geographic Information System (GIS) that runs on Linux, Unix, Mac OSX, and Windows. QGIS supports vector, raster, and database formats. QGIS is licensed under the GNU General Public License. QGIS lets you browse and create map data on your computer. It supports many common spatial data formats (e.g. ESRI ShapeFile, geotiff). QGIS supports plugins to do things like display tracks from your GPS. QGIS is Open Source software and its free of cost (download here). We welcome contributions from our user community in the form of code contributions, bug fixes, bug reports, contributed documentation, advocacy and supporting other users on our mailing lists and forums. Financial contributions are also welcome.

Source www.qgis.org

Arc View 3.2 on Ubuntu Gutsy

Hello Ubuntu user, if you an GIS, Remote Sensing or mapper you do not have to worried about the the arcview software that does not work on Ubuntu. Because you can use the emulator (wine). so you can install this software via WINE. It is works well, like 3D analyze.
Several months ago this software still has problem, the legend was not appear what it should be. But know it is already work.

Good luck