C
C++
php5
Python
MySQL
MatLab
Mathematica
Visual Basic
Pascal
C#
HTML
IGOR
Javascript
Java
gnuplot




some useful links:
pastebin

Notepad++

TeamViewer
(remote desktop, cross platform)

pdf Split and Merge
(pdfMerger)

pdfcreator
(standard pdf creator)

Gimp
(Gimp 2 for Windows)

GNUplot 4
(GNUplot for Windows)

Texstudio
(TEX)

inkscape
(free Corel Draw, Vector Image)

filezilla

Eureqa (Formulize)

IGOR Pro

Wolfram Alpha (Mathematica)

Handbrake (Video Converter)

VirtualDub