Ralph I have read about Desert Snow in many different threads on this site, almost anyone on this site will recommend, aspen, coconut, desert snow, newspaper or paper towel.
I personally wanted to use the desert snow but it is pricey compared to aspen, So i went with aspen in my 20gL tank, got a huge bag for 20$
I would say, if the desert snow is in your price range, then do it, it would look cool seeing your ivory girl disappear in it!!!!
Here's a thread on substrate, might help clear some questions up!
http://ball-pythons.net/forums/showt...ht=desert+snow