Like imsewnso I sometimes wish I hadn't accumulated so much fabric. I keep my yardage on open shelves, FQ size pieces in little open boxes, and smaller scraps in clear plastic shoe boxes. It would probably be better if I could protect everything from light, but that would mean not seeing the fabric, and that would probably result in my not using it.
The important thing is to protect the fabric from moisture, light, bugs, children with scissors, anything that might harm it. However, as long as you take reasonable precautions, you don't need to obsess over how you store your stash. We all find different solutions that work within our space and budget.