Yelp is really helpful to narrow down the bike shops that are good:
http://www.yelp.com/search?find_desc...desc=bike+shop

Another mark of quality is the involvement of the bike shop in the local biking scene. As you are thinking about becoming a roadie you would want one that is active in the road cycling around the city: organizing bike rides, road races, having a club and team, sponsorship, etc.

Then, go visit and see. Different bike shops are run by different people and would approach service differently. They might all be good objectively speaking but you have your own expectation of what constitute a good service.