Mike, blogging over at Waiving or Drowning has a bit to say about the (Product) Red campaign, which encourages consumers to by products that are supporting AIDS reserch with part of their profit. Mike critiques the fact that the only way some will give to great causes, is if it is part of their consumeristic habits. As a result he set up an alternative campaign, (RED)EMPTION, which is designed for those who aren't inclined to spend $100 or more, to make a $10 donation. They think we should simply donate $10 or more directly to the cause. I think you should really check out both campaigns.
My take, we got to give generously. Then, if you were going to buy something anyway, you might as well by a product that gives back to the common good. Having said that, do we really need half the junk we buy? Rather than buy a t-shirt for $20 from the GAP, which will donate 50% of the profits to AIDS research, don't buy the shirt and donate $10 or $20 directly to the cause.