i would vote for an alcohol stove, because they are light weight, inexpensive, burn clean with no smell and the fuel is cheap and readily available almost anywhere.

i checked out a lot of designs before settling on the one i made. its made from a soda can but out of 3 pieces which give it an inner and outer wall, its super efficient and doesnt require a pot stand. i can boil up 2 cups of water in 4 or 5 minutes and it only takes an ounce of fuel for 10 minutes of burn time which is enough to cook most survival types of packaged food.

aside from that i made myself a wood gassifying stove. it's not as small and pack friendly as the alcohol stove, but its still light weight and relatively small.

an old survivalist dude told me once that its a great idea to pack both of these stoves. to use the alcohol stove when you need to be covert, because it puts off zero scent. and to use the wood gassifyer when you aren't worried about it.

i have pics of both designs around here somewhere, i'll have to post them up.