In reply to Scott_M@c:
Depends if you are going to mountaineer, if thats the purpose of the trip.
If not, i used STA top level insurance ("premier"level i think), which covers you for an incredible amount of things including being over 3500m and mountaineering, they just shouldn't be the purpose of the trip. Worked out at about a pound a day for me for a 12 month trip.
H