I think along the same lines, Harmless. It usually finds me rethinking my carry every season as the pack gets too heavy.

I'm currently working on PSKs for the friends I go fishing with every year. I want something small and unobtrusive for them so that their eye rollling isn't followed with them leaving their PSKs onshore. I need to figure out the maximum so they'll stick it in their pocket when we hit the water, as well as the minimum to actually make it effective. (Without me breaking the bank either.)

We all carry water bottles, full tackle boxes (with line, lures, hooks, pliars, filet knife, etc.) and a travel mug with coffee.

So far I have assembled the following in small digital camera bags:

-whistle
-disposable rain poncho
-mini bic lighter
-vaseline soaked cotton balls
-led keychain
-mini FAK with bandaids, polysporin and a few gauze pads
-bandana
-micro pur tabs
-small multi-tool

EDIT: I'd like to add a container for carrying water as well.