The cheapest, once I've ticked the winter sports button. Read the small print, check it covers injuries, emergency transport including helicopter and extended stays in hospital.
Some might cover hotel stays for dependants as well. My mother in law had one hell of a fight when my SiS broke her leg some years ago to recoup the hotel and lost flight because she stayed to hold her hand. I'm not sure if they cover this or not but it's a question worth asking.
Don't ski off-piste. If you do ski off-piste don't hurt yourself because I've not found an insurer that covers this and I'm not good enough at skiing to ski off-piste without hurting myself.
Caveat, we don't have children so do approximately half of the above things to check.