A mentor of mine in the financial services field.
How you look has nothing to do with how you do business (apart from going sly giving you more confidence that is). Some people here say a shaved head is a no-no in certain fields because it doesn't look good, that's bollox ('cuse the French). Anyone who doesn't respect you in business because you're bald is obviously a jack-ass.
Edit: 'course if you're a professional you're there to work, not to judge peoples hair styles (or lack of-).
Last year at my school, I applied for a co-op program at my scool at a restaurant, and it was at the end of the previous year before I attended. When I first went, I had lots of hair. When I came back to the restaurant 4 months later to start the program, the employer told me I looked a whole lot better, and more respectable bald, then I did with hair.