Well, let's see:
I know I'm part French and part northern Italian (more Swiss and French than what is normally thought of as Italian). I think I might be part Scot and part Russian, though I'm very unsure about the last one; my surname is unmistakably German-Jewish.
Really, though, I don't care very much. I don't identify with any of these nations/ethnicities. I identify with who I am, not with who my ancestors are or were.