Colorado Backpacks.. I do a lot of off-piste skiing at Winter Park/Copper/Breckenridge/Crested Butte (Cliff drops). It's good to have a little bit of back protection for some gnarly landings.
I also volunteer as a patrol at Winter Park. So it's good to have all of my medical gear/shovel/probe.
So on my hill, where avalanches are prone to happen, I have my gear.
Also, I can carry a lunch, spare gloves, and I always carry spare goggles from a white-out incedent I had in which i hit a tree with my face, broke my goggles, and had to ski in a blizzard with nothing.
(p.s. I'm not a wanna-be-cop patroller, Don't yell at me... I only yell at people if they're being idiots. I'm really only into it for the medical experience and free skiing)