Muslims need no reason for doing charity as they take it seriously. For them, charity is way to worship Allah. The needy and poor pray to Allah for help and they get help. Allah gives wisdom to Muslim people so that they collect funds and buy relief material for the needy and poor.
If you are looking for best charities to donate to then visit website of an Islamic charity group and get many reasons to do charity. Presently most of the charity groups are collecting funds for buying winter relief material for people of Iraq and Syria. They have made winter kits containing blankets and warm and woolen clothes for poor families.
If you are serious about helping a poor family then you should buy a winter kit for a family. All you need doing to buy a winter kit is to donate cost of a winter kit to a charity group. Or you can buy a couple of kits for a couple of families. Or you can donate funds to some other cause.
Pakistan is suffering from its worst flood and it needs quick help. Relief material is being sent to flood hit areas of Pakistan and the material contains food packets, clothing and medicines. If you want to help in flood relief, you can donate money for this cause.
You would find a charity group working on different projects like providing pension to widows and adopting orphans. You can find a project or cause to do charity and you can donate any amount in charity.