I would like to upgrade from the novelty plastic bin I currently use for cookies. What cookie jar features would prevent the cookies from getting stale for the longest amount of time? What shape of jar will allow for storing the most cookies? Is light sensitivity a factor?
I've found a cookie jar buying guide on Walmart.com that has some interesting tidbits. For functionality alone, looks like a glass jar should do the job well. Something like this would have an advantageous shape to make cookies easier to reach, and the jar less prone to falling.
One feature you may want to look for specifically would be an hermetic sealing lid, which would help keep moisture in the jar and slow down the drying. Same kind of jar that is often used to store flour, sugar, coffee, beans, etc.
Is light sensitivity a factor?
I don't think it would be, in most cases, unless you kept your cookies in an area that is heavily lit by the sun.
One thing you can do for anything which goes bad (rancid) due to oxygenation is to spritz into the jar a bit of canned air sold for keyboard cleaning. These cans contain a refrigerant gas which is heavier than air, so even a little bit in a bottle or can of oil keeps the oxygen away from the oil.
It will work with cookies and other things as well since it stays on top of oils, you only need to hit them once. I don't know about cookies...they never last long enough to go stale!