You'll probably have better luck on viewsfromthetop.com's northeast forum. But, really just about every 4000 footer in the whites can be reasonably done as a dayhike if you're in good shape. The classic white mountains hike in my mind is, the old bridle path/falling waters loop across the summit of lafayette. This sometimes, perhaps often, warrants crampons as well as snowshoes though. Moosilauke is another winter favorite of mine, and perhaps less crampon dependent on average.
I'm trying to plan a day snowshoe trip in the Whites, ideally a 4000 footer. Anyone have any ideas for a reasonable/good shape hike--especially a loop.