The “No Credit Needed” blog hada great suggestion for curbing those impulse buys.  Just like a waiting period for buying a gun, it suggests implementing a waiting period for large purchases.

I’ve always done this somewhat, simply by refusing to pay full price for items.  My cooling off period happens in those weeks or months that I’m searching for the  best deal possible.

For every $100 that I want to spend on the purchase of a new product, I must wait one day before I make the purchase. This creates a self-imposed ‘cooling-off’ period.

[more]If you truly suffer from MustHaveItNow-asitis, you will definately benefit from implementing this in your own life.

No Credit Needed
http://www.ncnblog.com/2008/04/23/the-100-a-day-rule-prevents-impulse-buying/