Here's something I found at SmartAboutMoney.org:
Wants are nice to have but are not essentials: eating out, going to movies, text messaging, or getting the newest cell phone and ring tones.
Needs are the essentials, the basics of life that you must have to survive: food, housing, clothing. Some expenses that relate to your job (that is, your ability to pay for the basics) also are needs, such as transportation to and from work, and health care coverage to keep you well enough to go to work.
There's nothing wrong with spending on Wants, as long as you have enough to cover all the Needs. AND that it fits within your budget and you're not just slapping it on a credit card!