I ordered a Jamis Coda Sport today, for riding with the kids and for occasionally riding to work. The manager at Harris Cyclery in West Newton recommended it to me, and a test ride convinced me. I had also been looking at the Trek 7.3 and the Specialized Globe Sport. For bike shopping in the western suburbs of Boston, I found the following places interesting:

Harris Cyclery
1353 Washington St.
West Newton, MA 02465
+1 617 244 1040
A very serious bike shop; also good for beginners.

Spoke-N-Wheel
119 Boston Post Road (Route 20)
Sudbury, MA 01776
+1 978 443 6696
This is the first place I went. I called to make sure they were open on the evening before July 4, and the person said yes. When I got there an hour later, they had closed early, and were closed all weekend. I would have liked to see what they had, but I decided not to wait. They also have stores in Westborough and Waltham.

Landry's Bicycles
790 Worcester Road (Route 9 eastbound)
Natick, MA 01760
+1 508 655 1990
This is where I looked at the Trek and Specialized bikes. They knew a lot about bikes, and I liked the store a lot. They have a couple of other stores in the area as well.

International Bicycle Center
71 Needham St.
Newton, MA
+1 617 527 0967
This is a pretty big shop, and they also knew a lot about what they were doing. I test-rode the Trek 7.2 and 7.3 bikes there. They have another store on Brighton Ave in Boston.

REI
Route 30 in Natick
+1 508 270 6325
As you might expect, the staff knew something about bikes, but not as much as at the specialized shops. I was surprised that REI was selling not-quite-as-good bikes for about the same prices as the bike shops.

Places I haven't been, but came across in looking for places to shop:

Ray & Sons Cycle & Ski
183 Main St.
Maynard, MA 01754
+1 978 897 8121

ATA Cycle
93 Thoreau St.
Concord, MA