There's an interesting debate that pops up whenever the topic of money and charity are involved.
On one side, you have people who feel that each individual has a responsibility to the success of the community as a whole. These are the people who feel that a person "should" give to charity, "should" care about hungry people in Africa, "should" contribute to fund cancer research, etc.
On the other side, there are people who feel that the world is a jungle. That the only responsibility one has is to oneself and (perhaps) one's family. These are the people who are likely to argue that giving to other people just makes them dependent upon the giver, and that you shouldn't have to give away your hard-earned money to people who haven't worked for it, etc.
Obviously, there are varying stances in between these two extremes, but for the sake of discussion, let's accept this simplified view of things, for now. From a purely objective and rational point of view, this comes down to an emotional appeal vs. logic.
Logic dictates that if you give away less money, you will have more for yourself. Logic also (seems to) dictate that if you have more for yourself, your life will be happier, particularly if you are below a certain threshold. (Research has shown that this threshold is about $40,000 per year.) You will be able to provide better for your children. You will even be able to buy more consumer goods, which will create jobs for people who are less fortunate, and eventually make the world a better place. If you eliminate a religious imperative to tithe, there's really no ethical reason to think that you "should" give away what's rightfully yours, whether you worked hard to earn it, or just happened to inherit it.
However, upon further inspection, I feel there's something that's always missing from these discussions. At some point, you will need help from your community. Whether you are a wealthy executive who needs advice on how to handle a marital dispute, or a poor divorcee trying to figure out how to keep your house and raise your kids on a single income, you will want to have a community of supportive people around you who care about you as much as they care about their own interests.
If you are a person who gives to other people, doesn't it make sense that you will gather people around you that are also giving personalities? However, if you are only out for "number one", doesn't it make sense that you will drive those "givers" away?
We create the world we have to live in by the people we attract. What kind of world do you want to live in?