From Boston, Waterville, Loon, Cannon should all be about 2-2.5 hours (straight shot up 93 north), Sunapee is about the same time frame (93 north to 89 North).
If you are looking for more than just park skiing, Killington, Sunday River, Sugarloaf, and Cannon are probably the best bet (in terms of offering more challenging terrain, but you might have to venture for it).
I have to disagree with the above poster about Okemo though, It's really not that big, and personally, I don't find most of their trails enjoyable, however, they have a couple glades that when open, can be a lot of fun, but like previously said, they do have some really good park features (spread across the area in numerous parks).
Something else to keep in mind is Crotched, decent park and offers late hours Fri and Sat nights, you can get a 9PM - 3AM ticket - if you're a night owl.
To give you an idea though, I'm about 30 minutes NW of Boston, and my trip times have been 1:45 to Loon/Waterville, 2:00 to Cannon (roughly), 2:15-2:30 to Killington/Okemo/Piko and I think about 3:00 to Sunday River.
However, if you catch a storm, Jay Peak cannot be beaten, but its a haul from Boston, probably close to 4 hours, but definatly worthwhile.
life is too short to have any regrets