I'm beyond the Altoid's tin fettish now. Having had a survival issue when I didn't have pockets, I now use this:

http://store.yahoo.com/cell-accessories/unwatpouc.html

It holds more than my Altoids tin. I've had to discipline myself not to put in everything it could hold. The lanyard is "breakaway" so you won't hang yourself. I thread my whistle, Photon II and compass on the lanyard itself. It has stayed waterproof when swimming, but I have not tested it at depth so I don't know yet about using it when scuba diving.