Louis Boston is definitely the best-known men's store in New England. Their first floor is where you'll find "designer" stuff: Helmut Lang, Jil Sander, Dries Van Noten, that kind of thing. The second floor is where you'll find the really good ready-to-wear stuff, like Loro Piana, Kiton, Brioni, Ralph Lauren Purple Label, Zegna Napoli, etc. The third floor is more for made-to-measure or custom-made stuff. Filene's Basement is where to go for off-price stuff. Peace, JG
Good calls, Joe G. You may also want to try and just walk down Newbury for stores like FCUK, DKNY, Aldo shoes and some other trendy boutiques. Also thinking maybe BR, and club Monaco, but it's been a while. I think there's also an Armani store with an Armani Cafe connected, however you obviously wouldn't look for bargains in there.
If you're looking to save money, you may want to take a little drive outside of Boston. Not far away, in Framingham, is a good outlet mall. Just a quick drive, right next to Foxboro (where the N.E. Patriots play), well worth a day trip. There's an Off Saks, Barney's, Hugo Boss, Versace, Joseph Abboud, Donna Karan, Polo, Kenneth Cole, Nike, Puma and lots more. Check it out.
There are many good stores in Boston, and outside- KAPS and Mr. Sid's are a couple other good ones.I'd agree with Joe G. that Louis is the best. In fact it's arguably the best specialty store in America- certainly in the top 5 along with Stanley Korshak in Dallas and Wilkes Bashford here in SF. Bergdorf is also up there, but people are always arguing over whether they're a true specialty store or not. As for the outlet mall, check under www.premiumoutlets.com.