Ordering on Amazon.. too much packaging?

I just placed an order for some books and cds on Amazon. And I bought some items used and others new. As I was preparing to check out I thought about the following:

Buying used is good for the environment: it reduced waste, reuses stuff that people don’t want.

Buying used stuff on Amazon is bad: more packages (packaging) coming from more places (polution from the shipping)

So what do you think? Is ordering from Amazon just bad, period? SHould I forego the cost savings of buying used items because of the environmental impact that results from multiple shipments and more packaging?

I didn’t go out and waste time, or burn fossile fuels to go to a store and get the stuff. I did buy through BooksWeLike.net so some percentage of my overall sale goes to some good cause or other.

In what now seems like cruel irony, two of the books I ordered? Paper or Plastic and Green Living. Perhaps when I get them they will shed some light on the decision.