Boston has everything, either in the city or right nearby. From museums to beaches, it's one of the most beautiful cities in the world. You can spend the day wandering around the MFA (Museum of Fine Arts) or take a day trip to the North Shore, South Shore, Vermont, Maine or New Hampshire. Drive up north during the early part of the fall to catch the changing colors of the foliage, or in the winter to go skiing. During the summer, check out the beaches of Duxbury on the South Shore or Marblehead on the North Shore. During the spring, the Public Garden is overflowing with beautiful flowers. It's also a great time of year to go to the DeCordoba's outdoor sculpture museum. If you're an architecture buff, go for a tour of the Walter Gropius house and visit IM Pei's JFK Museum. If you're a shopper, Newbury Street is a must - also the place to "see and be seen".
Newbury Street is also home to Sonsie's, a great place for brunch, dinner or just drinks (they have a wine bar downstairs). Another favorite is the Marliave near the park and Beacon Hill - try their gourmet mac & cheese!
For a boutique hotel experience, stay at the Ames Hotel (around the corner from the Marliave). No 2 rooms are identical, and the location can't be beat. Plus it's a fantastic melding of historical and modern architecture and design.