Wow, what a wonderful set of choices!
If you like skiing as well as boating, Grenoble, hands down. I spent a winter in Val d'Isere once and if you can imagine stitching lifts from Breck to Copper to Vail, well, that's what the resorts are like over there. But with twice the vertical and with a lot more rad skiing. And incredible spring skiing as well. You'd be 2 hours from Val or Chamonix, an hour from Trois Valles, and there are national parks all over the place down there. I don't know anything about the boating there, but being in the south of France would be just like, well, being in the south of France and you'd be at the foot of the French Alps. As opposed to being in Scotland, which would be great if all you wanted to do was drink while it rains outside and then go boat icewater under gray skies.
Even if you don't like skiing, Grenoble
Good luck with your decision!