German, English, Irish, Dutch, Creek, and Chickasaw. I know I have more ethnicities than this, but this is the all I know at the moment mostly because my Dad's family has a past that is hard to dig up. Still, I have some interesting combinations right here already. Should be interesting to find out more.
Since I have German roots from both my Mom and Dad, I guess that makes me mostly ehtnically German by plurality. However, my European ancestors arrived in America in the 17th century (possibly earlier from my fraternal grandpa's side) so that pretty much means I am about as Americanized as it gets.