I was at Wheelworks in Belmont last week (first time). They have a decent selection of bikes. I found they have the best assortment of accessories I've seen yet compared to other bike shops. You may also want to check out Innterational Bike in Newton. They also have a very good selection of bikes on hand. I bought my last 2 bikes there (Gary Fisher Zebrano and a Trek 2.1 spa). When I bought my first bike there, I found a bike I liked but it was a little small, Test rode another to check out the size. They ordered the one I liked in my size, it only took a couple days to ship it from thier warehouse. They allow you to take it for a decent test ride as well.
But the best advice is to do some research online, then hit a few bike shops (take notes). Then do more research before the purchase. And remember a good fit is the most important. If you don't think the bike shop is getting your friend a good fitting bike, go to another shop.