I used to cross-country ski in the midwest, tried it and gave up in the more hilly PNW. I mostly snowshoe now. I do ski occasionally, when I do I rent packages from REI - they have some good advice on choosing skis and equipment, have a look: http://www.rei.com/expertadvice/articles/crosscountry+ski+touring+gear.html. afaik both Rossignol 65 and 70 are good, they resemble what I rent. The BC70 may feel better because they are wider, give you more float on the snow, and may hold your weight better. If you're not sure, rent the BC65 somewhere one more time before you buy it. I'm all for the most comfortable ski when the price difference is $100.