This is a book I'll be picking up a copy of, eventually: Not Buying It : My Year Without Shopping, by Judith Levine.
Levine takes the plunge and attempts to not purchase anything for a year, documenting her endeavor in the process. I believe she made an exception for food and "necessities" but defining what was a necessary was an interesting process. It appears she reflects on the realities of the project, and struggles with what it means to cut back, which is what I find intriguing; I hope it will be a good read.
Or, you could try it yourself by not buying the book, for starters. Heh, heh.
I've tried something similar myself, partly to cut back on spending, partly to reduce worthless clutter.
It's not as easy as it first seems, especially when you're used to "retail therapy" or visiting eBay to purchase junk at the drop of hat (What a bargain - I must have it!).
As the buddhists remind us, nothing is permanent, so it seems silly to get attached to objects which will merely cause us more stress when they break, get lost or are otherwise taken from us.
And, as the environmentalists remind us, all that stuff comes from somewhere, and eventually it goes somewhere. If you think you really need something, think how it will look in a landfill...