Linux on windows: Cygwin

If you use applications that work on only windows (like gtalk, voipcall clients), then you feel like having linux environment on the side, so that you won't have reboot into linux for doing your work. For these people (including me), Cygwin is a good choice. For instance you can have the bash shell, emacs, gnuplot, xfig, gvim, latex, xdvi all at one place ...  The installations is very easy.  Don't forget to install X server of cygwin (cygwin/x) during the installation process. Particularly, latex is more neat to use on cygwin than installing miktex and other tools for the same purpose.