I prefer a zippo when backpacking as a primary source of fire (I have several others, don’t worry) — it’s rugged, I can store extra flints in the base under the first layer of cotton, the wind doesn’t put it out, and if my hands are frozen it’s still easy to light.
The traditional downer is the one you mentioned - the fuel evaporates in about 10 days after refueling. That also means that your clothes stink of naptha, making them useless thereafter (without several washings) for deer hunting.
A post on another forum suggested getting a bicycle inner tube (~$3 at wally world, or free if you happen to keep them around for a source of high-tension rubber bands) and cutting a band the length of the zippo (i.e., cut a piece of tube about 2” long). Insert the zippo into the band — it will fit snugly with a slight amount of stretch.
My last trial with this method kept the zippo lighting for almost 2 months without refilling. It also keeps the lighter from banging on my keys, etc. in my pocket or from opening inside my pocket.
To answer your other question, a zippo can operate off most napthas. Coleman white gas is actually naptha, not gasoline, and will serve well. Charcoal lighter fluid is also a naptha but usually has a higher combustion point than zippo fuel or Coleman white gas, probably because of the propensity of most guys to spray it on the fire straight from the bottle. Using high-flashpoint naptha as charcoal lighter is a sound litigation avoidance strategy. It will work, but it will take more strikes to light and might need to be warmed in your pocket first. (for more information on naptha see: http://www.ask.com/wiki/Naphtha)
What?!? You're not supposed to do that? I thought that was standard grill operating procedure.
Yes, I'm joking... maybe.