The herb & spice section of my cupboard is crazy crowded, and putting a spice rack on my wall would really help out on the spice-finding front. But I've always heard that it's best to store your herbs & spices in a dark place, so I've been hesitant to take them from the dark cupboard and put them on a shelf on the wall, where they'll be more exposed.

Does anyone here know how much herbs and spices really degrade in light? And whether the type of light makes a big difference (energy-saving fluorescent vs. sun)? And whether there are some spices that can handle it better?