Should you be judged by what you wear? Perhaps not, but the reality is, of course, that you are judged. Throughout the entire job-seeking process employers use short-cuts — heuristics or rules of thumb — to save time. With cover letters, it’s the opening paragraph and a quick scan of your qualifications. With resumes, it is a quick scan of your accomplishments. With the job interview, it’s how you’re dressed that sets the tone of the interview.
How should you dress? Dressing conservatively is always the safest route, but you should also try and do a little investigating of your prospective employer so that what you wear to the interview makes you look as though you fit in with the organization. If you overdress (which is rare but can happen) or underdress (the more likely scenario), the potential employer may feel that you don’t care enough about the job.