In the United States--at least, among people my age (sixties) and in my region (Northeast): In a business situation, or between two people who've just met, or between casual acquaintances, people shake hands. No kisses or hugs are exchanged. In a social situation--for example, arriving at a dinner party at somebody's house--two women, or a man and a woman, may exchange a quick "peck on the cheek." Two men do not usually kiss on the cheek. Quick hugs may be exchanged between close friends--very often for a pair of women, less often for a man and a woman, less often for two men. In the United States men do not expect to be kissed on the cheek by other men. If a man from another country kisses them on the cheek they will be surprised and recoil. It is a small cultural misunderstanding, not serious. An unexpected cheek kiss from a foreigner will be laughed off. In the U.S. there acceptance of gay and lesbian relations. There is also increasing sensitivity toward any difference in treatment between men and women in a career situation. Because of this, customs are probably changing.

It depends how well they know each other and the occasion. In a formal setting both men and women will usually shake hands. If they know each other well the men will still shake hands and the women may hug or kiss each other once on the cheek. The same applies to men and women who know each other well and have a platonic relationship

It's just the same here, except exchanging kisses men. Also, if a man is close with a girl in a friendly way, they also may exchange friendly kisses on the cheek.

hand shake, hug and kiss on the cheek ;)

In Los Angeles because of the multi cultural environment, it depends on the ethnicity of the person you are greeting. If European we would kiss on the cheek, Asian we would bow, and American hand shake, hug, or slap on the back. I hug a lot of customers like they are family.