Don't really know if it qualifies as "gear" but hands-down the best purchase has been our whole-house generator. There is something extremely satisfying when the electricity goes out and after 10 seconds you hear the "vroom" and everything goes back to just the way it was. Number 2 would be my original Leatherman tool. I've used it hundreds, perhaps thousands of times in all sorts of situations and it has always come throguh for me. Third I'd probably go with my S&W Airweight J-frame in various versions. Haven't had to use it but it has given me a feeling of peace and confidence many times.