This is an interesting situation, but if I had to pick a goalie I'd go with a non 2011 prospect like Hackett or Salak. I voted for Hackett because his path to the NHL as a starting goalie is presumably is going to be a lot smoother. Kuemper is the only goalie standing in his way and he could possibly compete for the starting job in a few years but Hackett should have the starting job in two years or three (maybe). Backstrom is aging and clearly isn't who he used to be, with Crawford he's a young goalie and has a lot of future ahead of him. He plays for one of the best hockey teams in the league and I don't think Salak will start over him in very many situations going forward. Gibson is a project, I prefer Chris of the two but they both need time and seasoning in junior and in the minors.
All things considered, Matt Hackett is the best choice here.