Tools
The best tools are somehow the tools which sourceforge.net has to offer. Most of them are easy to use and will not consume all PC ressources. They are having everything in it what a scripter/coder/artist needs additional a clear and organised GUI most often. Else there is so many free software in the net. Awesome little programs (easy to use) with everything you need and which don't need a mega installation.
Notepad++ 
It is a source code editor. A real mighty one with many Plug-ins. Can be used as
a replacement for the ugly MS Windows Notepad, too.
Gimp
This is a GNU
Image Manipulation Program with Plug-ins.
XnView
Is an efficient
multimedia viewer, browser and converter. Many Plug-ins available.
Google
Earth
Google Earth lets you fly anywhere on Earth to view satellite imagery, maps,
terrain, etc. It is for mapping accuracy.
