Very cool software
This list is a little outdated, I’ll add more to it eventually…
Here is a list of some of my favorite programs:
Synergy
Control multiple computers with one keyboard and mouse. (copy and paste works too)
Scite
A powerful text editor with a stand alone exetutable.
Notepad++
A more powerful text editor than Scite, but not stand alone.
Hamachi
Zero configuration VPN. (useful for playing “LAN” games from the other side of the planet)
Mumble
A VoIP program. It lets me talk to my friends while playing games 
(and it works in linux)
VLC
A cool video player that can play almost any format without hassle. It also can stream video (I can play a dvd on one computer and watch it at another).
ghc
The Glasgow Haskell Compiler. A very good compiler for the programing language Haskell. My favorite programming language.