vbreslow: We loved being in the Copley/Backbay area. The Sheraton location was extremely convienent to the T, the Prudiential Center and to Fenway. I think it also depends on what your interests are and who is traveling with you.

As far as what to do in two or three days...I would walk the Freedom Trail not only for the history but also because it runs through and near so many places that you should visit anyway i.e. the North End, Boston Commons etc. If you take it at a leisurely pace, it can take an afternoon and early evening which works well with an early dinner in the North End which is a must. We enjoyed the view from the top of the Pru and loved our unofficial Harvard tour. If you like baseball or it's history, a tour of Fenway is a must! If you need more specifics, just ask.