Hi Ricardo,
Here is the rundown:
The best golf within 50 miles of Boston is (not surprisingly) private. The order of things from best on down is generally something like:
TCC/Essex/Myopia/Salem/Charles River/Old Sandwich/Boston GC/Winchester/Plymouth/Concord. After those, there is a hugely strong second tier that includes (in no order): Brae Burn/Woodland/Weston/Vesper/Tedesco/Kernwood/Turner Hill/ Renaissance/Cohasset/TPC Boston/Blue Hill/Wollaston/Weston/Pine Brook/Oakley/Dedham/Belmont/Wellesley/Oak Hill, and a few others that I'm surely forgetting....Duxbury/Spring Valley/Framingham/Marshfield/Marlborough...
On the public side, there is much more debate, as the top tier publics are wide-spread, and all are probably at best at the level of the second tier above. On the modern side you have Red Tail 65 miles NW of Boston in Devens, Waverly Oaks in Plymouth (RT and WO by Silva), and the PineHills duo (Rees/Nicklaus design), also in Plymouth...all four of those are pretty good, if unspectacular. Two more decent modern ones are Shaker Hills in Harvard, and Butter Brook in Lincoln.
On the classic side you have George Wright, a VERY good Ross near the city, Franklin Park, a short course that is the second oldest public golf course in America, dating to 1895, with a ton of history and great old timey feel, and South Shore CC by Wayne Stiles down in Hingham (15 miles south of Boston). Out towards Worcester I can vouch for Wachusett CC, another very playable Ross course.
Let me know if you would like further detail about any of the above, as I have lived in/around Boston for all of my 32 years!