I love the Charles Hotel in Cambridge. It's incredibly well situated -- just off Harvard Square -- and within walking distance of lots of great stuff. Additionally, Boston is a small city so a taxi ride over the river and into the downtown area is no more than about $12, which really isn't bad. Public transportation is definitely do-able, as well, but I was treating myself to an indulgent, taxis-only overnight! The rooms are nicely appointed, there is free wifi and a lovely modern feel. My room was a corner and the views were really lovely, especially at night. Henrietta's Table is a terrific choice for breakfast, in particular, and it has a mellow and nice bar scene in the evening. The service is great. Incredibly nice staff! Overall, a great choice!