Le Massif powder is insane... I went 2 years ago, got like 40cm's on the first day, and three days later I was still getting first tracks on stuff, it's insane!
Stoneham has some great park stuff... I find St. Anne has a lot of people who don't know how to ski too well and get in the way... then again, last time I was there was the middle of March break, so I'm sure that didn't help...