You fit a camel bak in your jacket? That seems awkward. They should make jackets camelbak compatible if the don't already. MRE's though would be reason enough for me to get a bag. My $.02.
I prefer a Bic. As much as I love Zippos, the bic has less smell, it doesn't leak, won't rust, and is slightly lighter. I like to carry both though. Zippos work better in the wind and inclement weather in general, and they are just plain cool.
Colt1911, I would advise filling them a little less. You may have to fill more often, but that fuel on flesh flat out sucks. I have also take off-brand and actual Zippos and put more cotton in them to help them keep from leaking. I've used gauze, but it doesn't work as well as cotton balls and even Q tip ends. Dentist cotton rolls like I use in my fire kit are probably the best things since they are so dense, but not necessarily easy to find.