[Kracka]

At least do business casual which would be considered dress pants and a dress shirt (button-up with collar). Toss a tie around your neck if you have one. I really don't think a suit would hurt though, for an office-based job its pretty tough to overdress for the interview. The worst thing that can happen is that you come in underdressed which is a big no-no.

From what you've said, I'd go with dress pants, dress shirt, and a tie. Remember, your belt should match your shoes and your belt buckle should match any other jewerly you are wearing (watch, ring, etc.)