Jewel cases are all good here!
I have some 7 year old Kodak gold surface DataGuard CD-R that still give a QS in CD-DVD Speed of 98%; Better than most of my current CD-R burns! :o
My current method of storage for DVDs depends on what's on them.
Important data backups and things like family occasions, weddings christenings etc I store in standard size DVD cases with low tension retaining rings. These are stored vertically in a drawer (dark) in England (cold, most of the time :bigsmile: )
My DVD backups are stored in 48 piece CD/DVD wallets; cloth lined inserts with see through plastic tops. These are fine for most discs although I have found that the cloth tends to scratch Taiyo Yuden DVDs. :rolleyes: All other disc types are fine with this material.
I don't give much concern to the storage of the DVD videos as it's no sweat to dig the original out of moth balls, but for unique data, hard plastic cases are essential IMO.