The following screenshots are programmes that I mostly use to help my works or I like to use. I don't have time to try all programmes on linux. I am interested only in computer graphics and data processing (including statistics).
Fig. 1. StarOffice is a complete office package, that can be run on linux, solaris, and windows. It can be said "you can do anything in one package" This package include office package, browser, email, flowchart, and drawing program. Lyx or KLyx is a scientific text editor program based on latex. Easy to use, like normally wordprocessing, automatic formatting layout with standard scientific report. Lyx's file can be exported as SGML, latex, and postscript.
Fig. 2. Examples of screenshot for some graphical programmes, such as Xfig, Tgif, Qcad, Xmgrace, Gnuplot, and Xgfe (X Gnuplot Front End). Xfig can be used for drawing from simple to complex map, like geologic map (not topographic map, that can be drawn with another GPL program, such as GMT (Generic Mapping Tools).
Fig. 3. Gimp is a perfect photo editor program on UNIX/Linux environment. This program can be run easier than other photo editor programmes like PhotoShop, PhotoPaint, Picture Publisher, etc. With scripting language called "Script-Fu" all of routine can be automatically done as a single command on Gimp. Xv is also a simple image manipulation program. The other image manipulation programmes that can be run on linux are photogenics, gphoto, imagemagick, etc.
The important thing is that all of these programmes are free (under GPL [GNU/General Public Lisence]).