Jay Peak- pretty much as good as it gets on the east. Jay has some of the highest annual snowfalls out of any other ski resort in the eastern United States.
Mad River Glenn- Doesn't necessarily have the highest snowfalls in the east, but still ranks up there and is a lot of fun on a powder day.
Sugarloaf- This is the only mountain in this list that I'm not speaking on from experience. I've been skiing there once and it wasn't a powder day. However the snow fields up top and bracket basin seem like they would be a lot of fun after a big dump. In addition, the plans to expand into Burnt Mt. would add tons of terrain that seems like it would be great on a pow day.
Killington- A few different parks to choose from, all top notch. The main park, Dreammaker, is always great, plus The Stash, while kind of a gaper magnet, is kinda cool too.
Mt. Snow- Carinthia. 'Nuff said.
Sugarbush- One of the most unique parks in the east cost, if not the country. Bush should be on the list for the creativity of it's features alone.
Okemo- has nice lodges and a lot of slope-side condo's, plus the whole jackson gore base area is pretty family oriented.
Stratton- has the village which is good for family's as it gives the not so serious skiers something to do if they don't want to ski.
Bromley- Less terrain than the other two, but from what I remember it has a whole bunch of activities other than skiing, plus Manchester is right near by which again gives those in the fam who might not be as keen on skiing something to do.