Think about what your going to be doing on a regular basis. Think about the kind of things that might go wrong. I spend most of my time in urban/suburban areas, and need to deal with minor cuts and scrapes more than anything else. I believe Doug has a section on first aid kits, and recommends having an assortment of band aids, different sizes, as well as the various types for knuckles and fingertips. I've found that to be quite useful, and for me, those are what I use the most. I also keep some meds in my FAK, a few OTC pain killers and some benadril (since I'im very allergic to cats, and never know when I might bump into somebody that has cats). As far as keeping a full supply of meds, I think thats better suited to a larger first aid kit, one that stays in the back pack or such. I look at my altoids tin FAK as something that can hold me over until I can get to my bigger FAK. Also, something that I just tried is vacume sealing items in the altoids tin. I have a stack of 8 2x2 guaze pads, and they took up a lot of space before. Now I have them vacume sealed in a single pouch (they are still in their wrappers) and they take up much less space.