I go with DSs aged 9 and 10 so we need bags with wheels as everyone needs to play a part transporting all the Stuff one needs to ski. Previously I have had one big one for me and weekend sized bags for the boys. Now they are getting so big that the Stuff takes up more space.
The bag could also do double duty for the boys to take on school residential trips - DS1 has a week in France in February. So probably a soft sided bag instead of a suitcase, as we need all the help we can get to be at least marginally cool 
Finally I have a obsession with recessed wheels, as the ones which are simply stuck on the bottom of a bag are liable to get knocked off by baggage handlers.
I am thinking North Face or similar in the sales. Big but not so big I am tempted to fill it over my baggage allowance!