I heard this morning of a man who horrified his wife by turning up for a management interview in t-shirt and jogging bottoms, rather than a suit.
There was a reason behind this: the job was operations manager in a factory, and he was expected as part of the interview to work on the production line. The company had forewarned him to dress appropriately. In these circumstances he did the right thing.
The moral is that slavishly wearing a suit for an interview (if a man) is not always right. You should instead strive to dress appropriately, but generally err on the conservative side. That means matching the general style in that company, and if in doubt call the receptionist to find out.