Too bad for Hulkenberg, but apparently Williams seems to need the money from Maldonado (as he seems most likely to get the drive atm). Barrichello is fixed as he can develope a car which is what Williams is really in need. Performance wise they should have kept Hulkenberg or get hold of Heidfeld...
Guess lots depends on the renault drivers and if Ferrari really wants to keep Massa. If they don't they could either get Kubica (who seems to get along with Alonso) or Sutil (haha) or Hulkenberg (as clear #2). Also Petrov isn't comfirmed yet either... I think the chance of a german replacing Petrov is quite high (Sutil, Heidfeld, Hulkenberg).
Btw: Are Trulli and Liuzzi confirmed yet?