From an American college perspective:
I hug my friends, male and female. (Although a few of my very good friends and kind of anti-body-contact so we hug very rarely.) My best friend and I kiss on the cheek/forehead/occasionally lips if we're trying to freak people out.
When I meet someone I usually shake their hand.

In my family I've always kissed my relatives on the lips, at least my parents and grandparents, but I'm now starting to realize that's really weird and go for the cheek kiss.

I met a French Canadian in Berlin and he did the double cheek kiss. The first time he tried to do it with me, I thought I was supposed to part of this instead of just standing there while he kissed my cheeks, so I ended up accidentally kissing him on the lips. It was super awkward and we didn't try it again until over a year later.