Maybe the next time the thing about "old white slave owners" comes up you can remind them that the first slave owner in the US was a black man named Antonio Johnson. The first black slave, (Johnson's), was named John Casor.
And not only black people were slaves, at least in the begining. They came in all colors.
"NO slaves were brought over in 1619, only indentured servants. All were freed after their term of service was up the same as Antonio Johnson. Indentured servants were freed after a length of time specified by either law or contract, slaves were not. Race based slavery was not established until the 1680's and Antonio Johnsons slave, John Casor, was the first person to be legally declared a slave for life by the courts, thus making Johnson the first slaveowner. Prior to that decision there were no permanent slaves in the colonies. Even after that white people, mostly Irish, could also be slaves until the 1680's decision barring white slavery. Native Americans could also be enslaved. It was not a uniquely black thing, like you would be led to believe today."
"The first slave owner in the US was a black man named Antonio/Anthony Johnson. The records are in the census from that time period. His slave was named John Casor and they resided in Northampton, Virginia."
http://wiki.answers.com/Q/Who_was_the_first_slave_owner_in_the_US"According to federal census reports, on June 1, 1860 there were nearly 4.5 million Negroes in the United States, with fewer than four million of them living in the southern slaveholding states. Of the blacks residing in the South, 261,988 were not slaves. Of this number, 10,689 lived in New Orleans. The country's leading African American historian, Duke University professor John Hope Franklin, records that in New Orleans over 3,000 free Negroes owned slaves, or 28 percent of the free Negroes in that city."
http://americancivilwar.com/authors/black_slaveowners.htm