Well, you can really have two winners here can you.
It all depends on what you meant by "bigger" you could say that "bigger" means larger in scale, filling the most of the cargo bay, or maybe weight\mass of the object.
Personally I really don't know all the cargo the Shuttle has taken into orbit, so I can't really say, I'm not much of a history buff. I can hardly remember what I did yesterday... oh look a butterfly! (ADD?)
or is it ADHD now... I forget.