Which is the leading facebook module for Drupal 7 a complete site integration?
You need FB. It offers all what you need.

I've been in the same dilemma and went with that one.

I suggest to try all of them and see for yourself though. Don't waste time with modules which offer third party integration - they rely on registration on those websites and usually paying a fee to them. I think it's silly registering and paying for a third party service in order to use another (free) third party service.