Most definitely HG, or more precisely the extraoral part, both the outer bow and the strap, whether cervical or high pull. The most interesting part, if I have to choose, though, is where the wire comes out of the mouth, especially when the mouth is shut. Hated wearing it myself, though...
Intraorally, it would be elastics - the more the better. In particular, though, elastics going across the front teeth, or going from one side to the other.