Perhaps this is an awkward topic for some, but the way you dress and groom shouldn't be a factor in how you're evaluated or perceived as a leader. By that I DON'T mean let your fun or freak flag fly--I mean, don't dress yourself as a distraction.
Things are more complicated today--when and how to be formal, casual, in between, etc.
For men this is easier, as the choices tend to be narrower. For women, who have a wide array of elements and choices every day, where do you get good advice on this? One sage recommended this site as a good place to start, and for some relevant advice.
The Recovering Leader