This was my first season skiing and I really got into it. One thing I noticed it that a lot (not all) of the skiers I met said that skiing is the only sort of excercises they do regularly. I would really like to see what some of the kids I met could do if they were in better shape. So yea I'm not a great skier but I do know how to work out.
Ok now for supplements
1. Everyone should take some sort of a multi vitamin, if you haven't been taking them you will notice improvements in your energy and focus within a couple of days. Plus they turn your piss a cool neon yellow. There are different 'levels' of vitamins you can take, I'll list them according to their price and intensity: 1. Something like Centrum, or the generic brand
http://www.psia-nw.org/articles/ski_conditioning_fitness.htm
http://www.askmen.com/sports/bodybuilding_60/87_fitness_tip.html
http://www.nationalgeographic.com/adventure/0511/sports/bode_miller.html