Free CSS Toolbox you can use this to write your CSS code, validating it and see if your CSS code works in other browsers. Free, Need installation.
PSPad editor with dictionaries in various languages for spell-checks; useful to code your pages, the one I’m using. Free, No need installation.
EasyPHP to write your PHP script without testing them online. Free, Need intallation.
the Gimp Don’t want to spend money on photoshop or paint shop pro? Then this is your solution. Free, Need installation.
Apophysis to make wonderful fractals. Free, the stable version need installation, not the betas.
ABRviewer Do you like photoshop brushes but you have paint shop pro? or the Gimp? Then use this useful tool to view the .abr files and create images from the brushes. Free, No need installation.
Aceftp wonderful. Free. need intallaton.