I've just realised, what a stupid thing to be arguing about - I feel sorry for the original poster who just wanted advice on his interview.
Mark - I apologise fror the arguing, in my opinion you should wear a suit, but please consider what others have said as well! And good luck
Jim - I'm sorry, I respect your opinion but I'm never going to attend an interview in 'smart/casual'. I don't feel it's appropriate for such a formal situation (not meaning to brag but I've got every job I've ever interviewed for and I believe that how I dress and present myself has contributed to that).