Best that I can do is Australian/British. It mixed in between them, but I love hearing British girls like the hot ones not ugly hammer to the face british girls :$
My best is probably my russian accent that sounds like the ones in the Metro Games, mainly bourbon and usually that rough sergeant voice that is reused over an over.
My best accent is probably English since it's easy to adapt to. The coolest accent however I'd probably have to go with Russian even though I can't pull it off.