Maybe you can expand a little on where you hope to find yourself - social service might mean different things to different people
Most schools have offerings in non-profit if that's what you want and from what I have seen, it may be one of those areas where you should just pick the best school you get into. Schools with a good international or entrepreneurship focus might be a good thing to look at depending on what you want to do.
"Egotism is the anesthetic that dulls the pain of stupidity." - Frank Leahy