In reply to StevenF:
The alpinism ones are good.
a) built in internal gaiters - which can be unzipped and removed!!
b) side of leg zipper vents and 3 pockets with zippers
c) velcro adjustable braces - which can be removed completely.
d) Strong crampon patches and Velcro ankle adjustment
e) Material is quite tough and mine show no signs of wear. OK I don't wear them a lot except winter - but I've got outdoor trousers I've worn less that show more wear!!
f) I don't need to wear any thermals underneath and for walking/ice climbing etc., in winter I find them perfectly adequate although my legs generally don't get cold anyway.