There is lots and lots of information available on what not to wear in the workplace — and what to wear instead of that not-to-wear stuff. Rather than try to synthesize it all, I’m going to provide you with some links to good information.
Check out “Do’s and Don’ts of Your Workplace Wardrobe” for information on why your appearance matters, as well as a funny slideshow on what works and what doesn’t. USA Today ran a piece in 2003 that gives the bosses’ perspective on work wardrobes (hint, board shorts and flip flops won’t help you get a raise). Christina Brinkley has a nice Wall Street Journal column on why dressing like your favorite Sex and The City character might not help your career (if you’re a woman); she has another really useful one that specificially addresses appropriate wardrobe choices for women in power. Finally, this July, 2009 ForbesWomen article on workplace style provides blunt advice on what does and doesn’t work when you’re looking to get hired, keep your job, or snag a promotion. Double bonus: it has a “what not to wear” slide show.