Thanks for the replies, everyone. We live in NC, so yes, temperatures will be over 100 and also down to freezing in the attic. I hadn't thought about the humidity issue (duh!) but that thought has put me off storing fabric in the attic. I like the shelves, but I also think the under-bed storage idea is brilliant, as I'm trying to keep my "footprint" down as much as possible. Thanks for all the great ideas!