If your website is intended to be more than just a reference point for your other marketing material, search engine optimisation (SEO) it is vital to make sure it is found by Google and Yahoo! etc and is placed highly in the rakings for your search terms.
If your website is not well optimised there is a good chance it wont appear in the first few pages of the major search engines let alone page one. Your competitors could be gaining clients that would be with you if they knew you were around.
More coming soon...