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.
http://www.getpaint.net/index2.html
There is also a plugin that allows to open and edit photos in the raw.
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http://www.flickr.com/photos/brate/
Nikon D40 w/18-135mm, Quantaray 70-300mm
Adobe Photoshop CS2 w/Eyecandy Plug in, Paint.Net (Open source Photoshop clone), Photomatix, Google Picasa.