I was in EBGames the other day and found the best case for the N800. It is semi-hardended (hard enough to prevent damage to the PDA if I dropped it), comes with 12 SD card slots, and enough room for the N800 and the headphones (and the headphones don't sratch the PDA).

http://www.gamestop.com/Catalog/Prod...oduct_id=67382