I think I must have been one of the few kids who was never that interested in LEGO. It is hard to choose the best because there are toys for different ages. As pre-school toys go, I always loved Mr. Potato Head and at school I loved the hula hoop. I also remember going through the Furby and Pokemon craze, and loving the slinky, silly putty, and beanie babies. I think the best toys are those that are timeless, and are enjoyed by kids of any decade.
I also think it's LEGO. LOGO toys are for all ages , even adults love to play around with it. They have also expanded their market by adding a range for girls called "Friends". So I would say that the best toy is LEGO.