what an interesting question!!!
It seems the crux of the debate is that a pizza box has become "dirty" by the pizza-y goodness and somehow that makes it garbage. Does cheese and grease make recyclable cardboard box not recyclable?
So, what do you people that subscribe to the "dirty" theory do with your soda bottles and cans? Do you rinse them out and put them in the recyclable bin or do you toss them out?
For the record, I put this particular pizza box in the recyclying cart. Then again, I was tossing some plastic bottles in at the same time and it was easier to open just one cart. I think I will have to ask the cleaning lady what she does with the pizza boxes next time.
Update: thg is right. It is the cheese and grease that make the pizza box worthless to recycling. Found the answer, ironically, at Yahoo! Answers via a Google "grease and cheese make pizza box unrecyclable" search.
Woo. Now I can sleep well tonight.