Calling a thread on this subject retarded is, quite frankly, retarded. Marion Jones disappeared from the track and field world after Balco, and her return hasn't been stellar. If, all of a sudden, she were to start dominating again, the skeptics would start their rants. Skepticism is normal, and Giambi's situation is one where it is justified.
Personally, I don't think he's back on the juice. Personally, I don't think it would matter if he was. The guy is a monster; steroids aren't going to help him swing that 40 ounce toothpick any faster. With his size, once he started hitting the center of the ball with the fat part of the bat again (it was always just a matter of time), the HR's started coming.