Free Software for cheap college students

Are you a cheap college student who doesn't want to pay lots of money(and don't want to pirate) for software? Here's a list of free (and open source) software packages alongside their expensive commerical programs.
CategoryCommerical softwareFree softwareOperating Systems Notes
Scienific computationMatlabOctaveWindows/Mac OSX/Linux Octave requires a little effect to setup but its works just like Matlab and will save you a lot of money! You also need GNUPlot to make plots. Some binary downloads of Octave already come with GNUPlot, just be sure to check. Be sure to download all the octave-forge packages to get maximum compatiablity.
C++ IDEMicrosoft Visual StudioEclipseWindows/Mac OSX/Linux Eclipse has a lot of plugins available, get the ones you need.
Word processing/Excel/PowerpointMicrosoft OfficeOpenOffice.orgWindows/Mac OSX/Linux Great alternative Office product. OpenOffice has most of the features in Microsoft Office. Requires X11 for Mac OSX.
NeoOffice
Windows/Mac OSX/Linux NeoOffice is a java implementation of OpenOffice for MacOSX. Does not need X11!
GraphicsAdobe PhotoshopThe GimpWindows/Mac OSX/Linux Requires X11 for Mac OSX.