there's really just one simple rule for this: dress exactly the way you are willing to dress at work.
if you underdress, and they give you a hard time about it, you might not fit in well at that company and you dodged a bullet.
if you overdress, there is a chance you will make your interviewer uncomfortable and not get the job.
dress in what you like to wear. its as simple as that. let them hire the real you, and not a front you put on based on some perceived image you have of the company.