Also, Magic Tailor (across from the Eaton Center) has been consistently good for me. I just picked up a suit that had pants hemmed, waist let out, and sleeves drastically shortened (with non-working buttons) for $60.
The only part I wouldn't recommend is working buttonholes. They're fine, and operational, but they have to send them out and they aren't as densely woven as other working buttonholes I have. The price is good ($50), but I wouldn't bother.