As a software developer I would never again take a job with a dress code. I feel that it's a very good barometer of management style. Recently (past year or 2) I have told several recruiters where to shove it on that basis alone. We are a scarce resource so companies need to buck up their ideas to remain competitive if they want to attract the best people.
The worst are those places who enforce strict dress code for some (male, non friend of the boss) employees and let the others wear whatever they want. I've worked somewhere like that previously and it's not a good environment.
Also I would really like to meet one of these "customers" who are so terribly fragile that they'd throw a contract in the bin over employees of a prospective service provider being dressed one way or another. They would be very fun to troll but I have a feeling that they do not in fact exist.