Any student who is planning to go for interviews should make the effort to get a nice suit, a couple of smart shirts and a couple of ties, ideally non skinny unless it's a role in a Jam tribute band. Make sure you are well groomed, your clothes are well pressed and creased and your shoes are polished with no holes in the bottom. Having recruited people for many years from office juniors, sales people to senior managers I can tell you without fear of contradiction an interview starts with that first impression and a smart apperance sets things off well.
It's about respect for the role and the process rather than adhearing to some standards of dress to fit in with the masses, a point often missed by those who take the "can't see the point myself", "why should I be the same as everyone else" or the "wouldn't want to work for a company like that who judged me on what I wear".