Dressy casual. Dress appropriately for the job your are interviewing for. For men- suits are not exactly needed, khakis and a nice dress shirt would do. Women- some kind of dress pant or chino paired with a nice blouse (not see through, and not too low cut) and appropriate shoes (Leave the stilettos at home).
Take it easy on the makeup and perfume for obvious reasons & avoid wearing jeans at all costs (too casual). Remember, this is still a job interview.
You want to greet them and leave them with a positive image to go along with your discussed skills.
Present yourself well. Be professional and friendly. Wearing business casual clothing is generally a good idea.
Workplace casual is fine. For men, jeans or casual pants and shirt is fine. For women, casual pants and top, skirts, what you would probably call dress casual. Take a look at what the other associates are wearing. That way you'll look the part. Closed toe shoes should be worn as that is part of the dress code.