I always wondered how much information we get from color. Things we see have different colors; edible products change color when began to spoil so we have a notion what color a fresh product should have. And the colors we see are very small part of electromagnetic spectrum.
So is there something special in the visible spectrum or any part of electromagnetic spectrum of the same size is just as good?
Answer
Both of the existing answers provide some really nice points; I wanted to try to piece things together a little more.
The solar spectrum peaks right around the visible part of the spectrum, so it provides the most possible light to utilize - shown in this figure: 
Shows the solar spectrum both above (upper orange line) and below (shaded regions) earth's atmosphere. The visible region clearly dominated the flux - and thus this is where one would naively expect photosensitivity to develop. Note that the peak flux appearing in the visible is also tied to where earth's atmosphere has high transmittance (see also: http://en.wikipedia.org/wiki/File:Atmospheric_electromagnetic_opacity.svg).
At the same time, the infrared (IR) portion of the spectrum still offers plenty of light --- and that's part of why many animals are much more sensitive (than humans) in the IR. At night, when the sun isn't out to illuminate things, the warmth of animals themselves is enough to emit enough IR for some animals to see. It then seems reasonable to infer that our lack of IR sensitivity has to do with our diurnal lifestyle.
Finally, the visible portion of the spectrum is especially sensitive to molecular features which gives us a lot of information about materials and their differing structures and compositions. Note that this is also what allows the mechanism by which our eyes work: when a certain molecular (see: retinal) interacts with a photon, it causes a conformal change which we detect.
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