A guy recently came through Missoula, MT. First visitor of the year to ACA's headquarters. His bike and gear, including a trailer and panneirs, tipped the scale at 181 lbs.
As Raybo notes, some people overpack in the sense they bring stuff they don't really need/never end up using. Others take what they want. And there are others who carry needless weight because they don't know better. For example, several years ago I helped a local couple get ready for a tour across the country. I followed their CGOB journal once they got underway. In a photo I saw they were carrying a full-size floor pump. They were not string cyclists by any stretch of the immagination and complained about even gentle hills. I sent them a message saying they should ditch the pump for something like a Road Morph G. They would because they were afraid it would break. I tried to assure them it's a tested product favored by many cyclists. They wouldn't listen. They were also carrying a large, cast-iron pot and numerous books. I got the sense they were trying to replicate life at home as much as possible. Not surprisingly, they abandoned their trip. Think it was in Texas. Surprised that they made it that far.
When I crossed the country in '99 I carried a lot of film camera equioment because I wanted to. Today, I carry a 5" Santoku knife because I cook elaborately and like the convenience of a good knfe. In the end, if someone is o.k. with their load, who are we to judge?