What Summerthyme and Dinghy said. If possible store them in their whole form - whole peppercorns, whole nutmegs, cinnamon bark rather than powdered, etc. No matter what form they are in they'll benefit from storage in a cool, dry, dark place. The kitchen is a terrible place to store herbs and spices except for the stuff in current use.
I store all of my bulk stuff in vacuum sealed glass canning jars. If I didn't have a vacuum sealer I'd use oxygen absorbers. Essential oils are the primary contributers to spice flavor and they are sensitive to heat, light, and oxygen.
This is a link to the section on herbs and spices in the <i>Prudent Food Storage FAQ</i>. It's essentially what we've said here.
http://athagan.members.atlantic.net/PFSFAQ/PFSFAQ-3-2.html#Herbs
I'm using peppercorns and nutmegs I bought back in '97 or '98 that I can't tell are any different than the last Penzey's order we bought last year.
Anyone got a good cinnamon grinder?
.....Alan.