When I deal with a company of any size, I want to be treated well. I want polite and intelligent salespeople, customer service reps. and tech. support experts.
When I write business plans for start-ups, I always ask what the plan is for customer service. To me, customer service is a key component of your business and marketing plans. You can have all the advertising and PR in the world but drive customers away with poor customer service. Not only that, but you'll gain great word-of-mouth advertising, if your customers are happy. That's because customers are more likely to sing your praises when satisfied and tell everyone they know how much they dislike your company when dissatisfied. They'll even tell people they don't know by broadcasting dissatisfaction on the Internet. Just think of the songwriter who put a song about United breaking his guitar on YouTube, or the current diatribe about cell phone companies in the NY Times.
You want great PR - great viral marketing - great word-of-mouth recommendations.
Zappos is a company that has become incredibly successful because of its great customer service. Business Week and Advertising Age have both run articles about Zappos's customer service recently. I highly recommend the articles: http://www.businessweek.com/magazine/content/05_49/b3962118.htm. Zappos essentially brings the shoe store to you via the Internet.
So as you plan how you'll start up or how you'll grow, remember to build in a plan for terrific customer service.