Easy-to-learn 3D modeling. Good for getting a sense of 3D space/perspective, lighting studies, exporting to Google Earth.
3D human posing software, with sliders to control gender/body mass/ethnicity/muscle tone/age. Exports in .obj format. Still in development.
Tree generator. Start with a dozen complex tree files or the basic default one, and apply extensive trunk/branching customization. Exports to Autocad dxf.
Scroll down in the freegis.org database for a long list of free GIS software
Microsoft Software Not really free, but paid for by your student technology fee
Alternative to Word/Excel/PowerPoint/Access
Alternative to Word/Excel, good for online collaboration
Alternative to InDesign/Framemaker