Just wear a suit. You can never go wrong wearing a suit. I wore a suit to the beach on Saturday after I finished work. Everyone loves a suit.
It's better to be over dressed than under dressed. I've always worn suits to interviews, both group and one on one. In one scenario, I saw the guy who was being interviewed before me walk out in chinos and a shirt with no tie. Even though he had 20 years on me and heaps more experience I got the job over him. I'm pretty sure it was because I was dressed better.