Cardboard On any given day this material alone counts for roughly 20% of my local transfer station's haul.
Paperboard This is the majority of food packaging, and covers most junk mail that isn't 'crumple-able'.
Food The amount of food we waste in the U.S. is staggering. Before my own family made conscious changes were were wasting 25-30% of everything we brought home. Thanks to variable work hours, even with careful planning we still waste 5-10% each week. If you think of the total mass of food you consume in a week, this quickly adds up across your local population. In restaurant-laden areas like San Francisco, especially with all of the buffets in Chinatown, the food waste is exponentially higher (did you see the Dirty Jobs episode where Mike spent a shift with the garbage collectors? Sheesh.)
Appliances (you'd be surprised by how many of these hit the transfer station every day. The workers line them up along the edge of the property, because their company sells the items to recyclers).
Since we reduced the amount of stuff we bring to the house, learned how to reuse a lot of stuff (such as composting), and learned how and where to recycle the rest, our 95-gallon trash bin only goes to the curb two or three times a year (and that's mostly due to shipping styrofoam and combination materials that cannot be recycled).