...eyes could see a greater range of light?

The human eye is capable of seeing light, or electromagnetic radiation, with wavelengths between roughtly 400 and 700 nm. When incident upon rhodopsin - a structure in the rod and cone cells of the eye - light induces a reversible chemical change in a molecule called retinal (a derivative of Vitamin A). This triggers a series of signal  cascades that send chemical/electrical signals to the brain, and thus allow the sensory information to be processed. 

Nowadays, science and engineering have made it possible to "see"  and use electromagnetic radiation of all wavelengths and frequencies. But what if mankind could see and/or process all light without aid of machines? What if we could "see" radio waves or "smell" gamma rays. If we could see radio waves, maybe we would have telepathy - we wouldn't need to speak, just transmit our thoughts via radio waves (we'd lose at least FM and AM radio though). If we could see infrared, perhaps heat from our everyday environments would blind us. If we could see x-rays, perhaps medical diagnoses would be faster and less expensive (though probably not >.<) .