It used to be 10 & 2, but with the advent of airbags most driving schools recommend 9 & 3. This is because the airbag *could* break your arms when it deploys.
Airbags: a bomb in your steering wheel: What could POSSIBLY go wrong?
Seems to me the spoke of the wheel would interfere with a 9-3 position. Someone else recommended 8-4. That accommodates the spokes, but I think it would be uncomfortable. Of course, not as uncomfortable as getting your hand blown off.