Having used the small butane torches and soldering irons for a while, I am going to have to go with my personal two favorites, that go with me anywhere I have anything electrical... (Thankyou xwife and kids for a truly useful gift) and has been probably the 2nd most used tool in the electronics toolbox. The radio shack adjustable output butane soldering Iron, Bright red, shaped like an oversized fountain pen, removable cap, literally fits in your pocket, and seems to have up to a 20 watt output, compared to my electric irons,
Note, in checking the Radio shack part number it looks like they have replaced it with a slightly
larger unit 50 watts now and not quite as easy to carry, Your local store may still have a few of the older Pen style, and they were/are far more convenient.
and the other is the
torch pencil #29440 from harbor freight this link will take you to a page where you can enter the item number manually... 28440
that little beast does everything from tinning and soldering 0 and 00 battery cables to tinning the 22 awg without blowing the solder away.
Second advantage of butane is light weight, more tip energy in the bottle than an equivalent battery setup ounce for ounce.
something like one of these is a godsend, and if I only had space to have one, it would be the little soldering iron.