There's a company called Seldon Technologies that is using nanotechnology in ways that certainly help the human condition. Imagine being able to extract clean water from sewage, or a scummy pond or other bacteria-laden source.
Think about the implications of that for places like Rwanda and Haiti, where clean water is scarce.
Forbes recently ran an article (here's a link: http://bit.ly/hNMeB4) on Seldon detailing one of its products: a nanomesh filter that could solve a multitude of humanitarian issues, as well as some market potential for things like air, fuel and other filtration.
Another example of nanotechnology making our lives better.