In general I don't make donations. When I make a donation I want to be sure that the donation actually goes to the purpose it was meant for. There are a lot of organizations that have caused me to think like this.
But there are things that can be donated because they usually go to a good use. I try to donate blood as often as I can (which is 3-4 times a year) because there aren't that many ways how blood can be abused.
And then there are the selfish donations. For some time now I've been trying to find a working Dell Wireless network card to donate to the people who work on the bcm43xx driver. The reason why I want to do this is that the support for this particular card is a bit buggy. The card works most of the time, but keeps freezing. Most of the freezes are small, about 1 sec long, but sometimes the card freezes for minutes. Even though the situation has improved quite a bit (the whole computer kept freezing) I'd love to give one of these cards to the developers to that they can make the support perfect.