I suppose it depends on one's definition of what a slave is.
You can interpret these definitions:
http://www.merriam-w...ictionary/slaveIn addition to that, when you are a slave, you are a slave to a particular person, place, thing, or idea.
As an American, I don't consider myself a slave to our government (if it is a republic, democracy, something similar, or any other form of representative government), at least not in the complete sense, regardless of what I think of the president, congress, etc. If you have the right to vote, then you are not a slave to your government. If those people we elect don't work out in the ways we hope, then we have the power to vote for somebody else. Slaves to a government don't have that right. We also have the right to run for public office, but you have to be really good at it to get anywhere.
But being a slave to the government is only one type of slave. You can argue that kids can be slaves to their parents or guardians, depending on how they are raised. You can in general be a slave to somebody else (for any amount of time: minutes, days, years, etc.) simply because they are forcing you to do something without getting paid for it.
By the raw definition of what a slave is, I think we have all experienced being one in some sort of capacity, but some much more than others. I believe that we are certainly not all slaves right at this moment.