ESBIT is by far the most stable of the various fuels typically used for portable stoves. ESBIT is very safe. It's actually a little bit hard to light. ESBIT is my fuel of choice for car trunks, caches, etc. It's a low flame velocity fuel, so you need a windscreen, but a bit of household aluminum foil or the lid from a caterers tray or the like will do.

I too get a little nervous leaving either gasoline or canisters of propane in my trunk, particularly if were there on an extended basis. There's a good safety factor on propane cylinders, but ... after 3 years or something? Dunno.

As for isopropanol, there are now stoves that will burn ispropanol cleanly. I intend to review one for my blog in the very near future.

HJ