I have not seem this program mentioned so I would like to put its name out there. Paint.net is an open source photoshop clone with hundreds of free user created plugins that can be downloaded from the forums.
There is also a plugin that allows to open and edit photos in the raw.
Nikon D40 w/18-135mm, Quantaray 70-300mm
Adobe Photoshop CS2 w/Eyecandy Plug in, Paint.Net (Open source Photoshop clone), Photomatix, Google Picasa.