I discovered yesterday when visiting a photography event (Zoom Expecience) that my computer screen is nowhere near calibrated and that my edited pictures look exactly right on my screen but on no one else's.
Of course I already knew that colour and contrast differ a bit per computer screen. I didn't want to take it very seriously though because I always lost my interest in the matter when things got too difficult. (What? Do I have to buy a sensor for this, no standard Windows option?)
As I realized that all my previous Photoshopped photographs are now kind of worthless, my interest in Spyder 2 Express suddenly increased. I will put some money aside for a new computer screen (the one I currently use is way too old) and a screen calibration set!