I started out with one of the prepackaged ones, but it quickly grew from there. Now I use an extra-reg bag for everything, including stuff specific to our own gear (like Mares straps, battery kits for computers, etc). While on our liveaboard last year, one of the other divers' Mares straps broke. I was able to keep him from having to borrow fins by loaning him one of our spare straps, so the kit isn't just to save our dives anymore.
