What Piece of Extra Safety Gear?

In regards to the messaging devices vs the acr plb,  I have seriously considered the benefits of being able to communicate with someone, but the deciding factor for me was stories I read of the weak power not being able to penetrate tree canopys, or broadcast from canyon-ous terrain. 
So I figured the messaging functions wouldn't be worth it if you couldn't use them because your'e stuck in less than ideal terrain without a nice, wide, clear shot to the open sky.  Plus having to go through a private network who receives your signal, then passes it on to authorities.  Wanted to eliminate that step. That just how it weighs out in my head.. 

And to address another recent post,  having this tool will in no way effect the time and energy I put into trip planning, or change how I spend time in the mountains.  I seriously do not ever want to use it and will take all the normal precautions pre and during trip.  I often go out solo, and having a plb now definitely brings some peace of mind.     

I carry an MSR reactor stove on almost all tours, even simple day tours. The weight of the stove + fuel is comparable to a full Nalgene, so it basically replaces weight and volume I'd be carrying anyway. An added bonus is the mid-tour hot lunch.

Other than that, a shovel, emergency bivy sack, and a down or synthetic parka are all that goes along on day trips. My thought is that I can dig a decent snow cave, warm up with the stove, and stay warm with the parka. If you leave the skins on your skis and put them in the furry side up with your pack over them, they make a decent sleeping pad, so I don't worry about packing a pad for day trips.

PLB and a rescue sled rig should probably be in the kit as well.