Jol or Bilic please. Sven's track record is clear: he needs a budget to succeed, and we clearly don't have that.
I'd go for Bilic. Out of contract so no fee, young with a point to prove, and very much in the tactical vanguard, which would make a nice change (he recently talked about formations saying "there are no lines anymore" which, though a bit mad, sounds like fun).
Also, it may be totally left-field but - Leonardo?