Before passing judgement on Bill Gates' charitable work, you should really read up on what he, his wife, and some other people are trying to do with his foundation. I think that if you read a little bit about the Bill and Melinda Gates foundation, you'll see that it is about a lot more than "improving his public image." Having worked on the foundation world for years, I can tell you that their intentions are a lot more honorable than those of many other foundation people. There are people on the full-time staff of his foundation who don't even collect salaries.
People all over the world are dying because of poverty, and he is doing his best to change that. Maybe he doesn't care about people getting a BSOD (blue screen of death), but I think its obvious that he cares about the condition of fellow humans.
I'm not going to comment on Steve Jobs's personal/charitable life because I don't know anything about it, and it's really irrelevant to compare one person's morals with another just because they have similar jobs. The only reason I know a little about Bill Gate's foundation is because my previous job was at an NPO, and I read a good bit about heir ideas on eradicating poverty, how much money their orgsnizatio gives, and how little they spend on overhead.
Oh, and yes, Bill Gates does run like a girl.