Over the years I think that I have tried just about all kinds of containers for storing dough, from glass, plastic and metal container (round are best for round pizzas as the others have noted), empty bread bags, plastic restaurant containers, and zip-type storage bags. I currently use mostly glass, like Pyrex glass containers (which member November suggested to me), or plastic containers. The best type of plastic container is one that you can see through, much like glass containers, to observe the performance of the dough, especially at the sides and at the bottom. For my glass and plastic containers, I drill a small hole in the middle of the lids. That allows the gases of fermentation to escape while retaining condensation in the containers. The holes in the lids are most beneficial if a fair amount of yeast is to be used. But if too much yeast is used, the forces of fermentation can be powerful enough to cause the lid to pop off. In cases like this, it might be preferable to cover the storage container with a hotel shower cap or a piece of plastic wrap.
For some other related tips that I have used over the years in relation to storage containers, see Reply 8 at http://www.pizzamaking.com/forum/index.php/topic,1508.msg13777.html#msg13777