I like to change my character's appearance to keep it fresh. I changed the armour colour about once an hour during the BWE. I don't know if ANet plan to implement a barber for release, but I really hope so.
Pretty much every MMO I've played makes you pay real money to 're-customise' your character (change face appearance/height etc.) but most of them (excluding Aion and Rift) allow you to change your hair/fur/piercings etc. for a small amount of in-game money. And I just cannot understand why anyone wouldn't do this.
Charging RL money for plastic surgery I understand but we should at least be able to change something as simple as hair/facial hair, or have the people of Tyria not invented scissors and razors yet?
If ANet still want a way to make money off of haircuts and such, they could implement this idea for additional hairstyles:
There could also be tattoo parlors added later on, as others have suggested in this thread. Extra tattoos could be sold later on as well.