Shaking Hands with Women

What is the ruling of shaking hands with the opposite sex. Especially in the corporate world where refusing to shake hands is considered offensive.

The Messenger of Allah had never shaken hands nor touched a woman's hand at all. Accordingly, scholars ruled that it is forbidden for men to shake hands with non-mahram women. In cases of necessity, it is permissible to do so. I, however, know that what some people in America consider a necessity, such as it being considered an insult not to shake a woman's hand, is not a necessity.