What is the best weight training supplement?

I have carried out a lot of online research and in doing so I am confusing myself. I want to start weight training seriously and my main goal is to get freakishly big and cut all body fat... ok maybe a bit of an optimistic target but may as well aim big (no pun intended). Exactly which supplements are the best... and I am looking for links to products or actual details not a response like "hey dude try going to the gym more" or "drink protein shakes"