It always seems like a bit of a cop out to get a high paying job so you can donate to charity- at the risk of sounding cynical, it seems like a way for people to try to have their cake and eat it too, i.e. I have a big income and can feel special about that, but then I can feel doubly special because I am so generous and giving it all away. I suppose it has some positive externalities, but I don't think it really even comes close to the spirit of charity.