I find the distinction usually made between worthy "need" and unworthy "desire" (or "want") to be pretty ropey. Usually, whoever is making the distinction assumes that they have a special insight into what people "really" need as opposed to the "artificial" desires that capitalism has persuaded them they want, i.e. that their desires are in the realm of false consciousness, while their needs are natural.
The problem with this approach is that it supposes the existence of a discernible human nature underneath the artificially imposed social mores of the day. But human need is far form being mere animal existence and must have an historical and cultural dimension, and, unless we are talking about some other people than these people here, that means the wants/needs they have as people in capitalist society.
I am always amazed at the willingness that some leftists have to rubbish the consumption habits of their fellow men and women. Sure, anything that is in your shooping basket can look pretty silly when it is tested against the olympian heights of the New Jerusalem, or perhaps nowadays of the Ecology. But who are we to say that people do not *need* nike trainers, or iPods, or cable television, or internet connections, or cars, or fridges, or formica work surfaces?
It is a truism to say that the basket of human needs would be very different if the society was different. After all, the basket of human needs is transformed very ten years or so even without any social change. Making exactly this point I used to quote a survey of 11-16 year olds who thought that they needed their mobile phones more than a fridge or a television. My point was that this preposterous response showed that needs were relative. Now I understand that the teenagers were right, and if not the fridge, then the mobile might still be more important than the television. They were just ahead of the curve.
Or as Shakespeare has Lear say:
"O reason not the need Our basest beggars are, in the poorest things, Superflous... Allow not nature more than nature needs, man's life's as cheap as beast's"
(There is an *objective* distinction between need and desire in classical Political Economy - though it is not one that most people on this list would approve of. It is the distinction between the consumption goods of the working class, that are necessary, and those of the ruling class which are by definition, luxury goods. Typically, the two markets interact in the sense that the latter is a model for the former - which is itself on of the civilising traits in capitalism.)
I develop these points in my little book Need and Desire in the Postmaterial Economy (1998)