There are all sorts "best of" lists floating around for ski resorts, but I wondered how much they change. Forbes did a Top Ten for Families list in 2011. In 2014, Forbes only listed a Top Five. Only Beaver Creek is on both lists.
2014 Top Five for Families - a Forbes article
1) Beaver Creek, CO
2) Heavenly, CA/NV
3) Park City Mountain Resort (PCMR), UT
4) Solitude, UT
5) Breckenridge, CO
2011 Top Ten for Families - a Forbes article
Beaver Creek, CO
Crested Butte, CO
Deer Valley, UT
Mt. Tremblant, QUE, Canada
Given that Vail Deer Valley bought Solitude and is doing upgrades for 2015-16, seems like it will continue to be a solid choice for families. Vail bought PCMR and is connecting it to Canyons by building a new gondola. That means 3 out of the 2014 Top Five are Vail resorts that are covered by the Epic Pass.
The 2011 list still seems like a good one for parents planning a family ski vacation. I'm thinking about families with school age kids, say mostly ages 5-12 with perhaps teen older sibling(s). The ski resorts I've seen mentioned in recent years that aren't on the list include Copper, Keystone, and Winter Park. Jay and Sunday River come to mind for the northeast. Any others?