There was one guy in a group of interviewees (~ 20 males) that was the only one not wearing a suit. Yeah, he stuck out like a sore thumb, but he still got in. He had a nice shirt and tie with some beige chino pants and still looked professional.
You can't go wrong in a well-fitting suit. If it doesn't fit well (sleeves too long, too baggy, pants too short, etc), that is actually worse than not wearing a suit, IMO. Whatever you decide to wear, wear it with confidence. If you're not comfortable in a suit, either get comfortable in one or don't wear one.
