While Led Zepplin was and is incredible, their sound basically stayed the same over the course of their recording career. Their live shows were just outstanding as well. To say Zep is the best isn't far from the truth, but that is bc so many bands emulated them. While VH is a part of modern rock history, they are a one trick pony. With David Lee Roth or Hagar.
I am seriously suprised nobody has mentioned Rush. They have consistantly changed their style from hard rock, to rock, to progressive,and many things inbetween, and had it all be incredible sounding as well as musically complex and demanding.