Bicycling has put together a pretty nice article on 29 “must visit” bike shops across the country. They have broken the shops up in to some categories which is nice. These categories include, food & vibes, speed shop, and women first among others. It’s a really nice list with some great shops. My suggestions would be Vecchios Bicicletteria in Boulder, Velo Cult in Portland, Denver Bicycle Cafe, and Golden Saddle in Los Angeles.