I've used the Printfile workbox for years to store my negatives. If you're not familiar they were tough plastic 3-ring binders that locked together, keeping dust out and protecting them. Well now I see they are discontinued. The closest you can get now is the Bestfile archival box, which is similar though smaller and not as nice as the Printfile was.
I'm curious how others using Printfile pages are storing their pages. Years ago I used to just use standard 3-ring binders, but got spoiled by how nicely the plastic box type binders protect my negatives.