Williams, Middlebury, and Bowdoin are among the best liberal arts colleges in the country. You could expect to find a friendly atmosphere, smart jocks, and great undergraduate physics programs at all three schools.
Williams physics majors have won several Apker Awards
in recent years (1999, 2002, and 2004). The Apker is a national prize awarded by the APS for undergraduate research in physics. Williams has been particularly successful of late, but I expect that other NESCAC schools have won Apkers too.