For me personally, buying a personal/mobile storage device is moot. Because I still can't trust a device which is essentially a HDD with moving parts, and once you dump your images from CF into it, it'll be like putting all your eggs into one basket. Makes me nervous. And if I were in that situation, I still would not re-use the CF cards on the spot.
(But maybe the personal storage device will be back-up in event of CF card failure?)
At the moment, I label my CF cards and place them in a solid plastic CF card case labelled "NEW". Buy several cards, and every 100 or so images, change card, and keep in another card case labelled "FULL".
And of course, I will keep my CF card cases close to my body by way of a neoprene pouch.