Hakuba DSM 60 digital Media Card storage Wallet
I store my CF and SD media cards in the Hakuba DSM 60 digital Media Card storage Wallet. It's made of a Nylon shell wallet with a Velcro closure. The Interior has netted pockets that hold up to 6 CompactFlash or SD memory cards. It's slightly "padded". This wallet just barely fits inside the zippered pouch on the inside top cover of my Lowepro 65-AW camera case. Since it's a tight fit, even if I forget to zip the pouch shut, the storage wallet will not fall out. Another benefit is that by storing it here, the Hakuba DSM 60 provides a little bit of added protection for the back of your camera, should something fall onto it while it's inside the Lowepro 65 AW
There are hard plastic cases that hold CF and SD cards but they are too thick to fit in the top of the 65 AW. Compact Flash cards are pretty durable, so I don't think you really need a hard style case.
You can still get the Hakuba DSM 60 digital Media Card storage Wallet. It's available at B&H for $6.95
When I fill up a card, I remove it from my camera and place it inside the wallet with the logo side facing away from me. That way I always know at a glance which cards have been used, and which are ready to go ! The smart folks at Hakuba made the pockets out of mesh material so you can see through to the cards. When you're in the business of working with cameras and camera gear on a daily basis, little things like this make a big difference.
If I'm working with "bare cameras" instead of working out of my Lowepro belt and holster cases, I just slip the Hakuba DSM 60 digital Media Card storage Wallet into my breast pocket. It's lightweight and slim...the larger, heavier hard plastic cases are too uncomfortable to have in your shirt pocket and they generally hold fewer cards so they are not nearly as convenient.