A reader at the PlayStation forums took the time and money to buy two different UMD cases, one from Sony and another from a third party called Score. The Sony one retails for $12, while the third party alternative saves you $3. Both cases hold 8 UMDs. After some thorough use, it appears that the Sony case is the winner. "The Sony case is worth the extra $3 by its design and is much more durable then the Score."
You can read the surprisingly thorough review at the PlayStation forums.
