Who is barbie's best friend?

Yes, but it's not Midge. Basically, Midge was Barbie's best friend, but she is no longer existing in Mattel.inc, because she moved on. So far, Barbie's "buddies" are now Christie and Teresa, but Teresa is mostly her "true" friend. Teresa always had been by Barbie's side, and still is. It would be a macabre thing if Barbie and Teresa split up abruptly.