Each and every one of my friends who is big on "Buy Nothing Day" (even to the extent that they pass out flyers about it in malls, etc) is the type of person who has an apt. loaded with unnecessary crap, loves to shop on days other than "Buy Nothing Day", drives a nice car, enjoys wearing nice, fashionable clothes, etc.
Those types of people passing out pointless "Buy Nothing" flyers right before returning to their own shopping the very next day just make me want to puke cause the whole thing is so pointless. It's a complete joke IMHO.
I have my own rule regarding buying pointless gifts. It is this: Unless I am buying someone something of real value that I know they'll use for sure (e.g., expensive watch, LCD TV, Mac, iPod), I ONLY buy people things that will be GONE after a while, and will NOT sit around littering these people's apts. or end up in landfills. That is, I give things that will be eaten up or used up, like cosmetics, tea, travel. Things that will be used up and are then GONE, like chocolate or soap or hand lotion.
I also give gift certificates that people can use for anything they like. My son's teenage babysitter got her first car and I gave her gift certificates from a GAS STATION so she'd have gas money, and she loved it.