It's similar to the situation the Sharks found themselves in with Nabokov and Toskala a few seasons back: two quality goalies, but only enough room for one. Sabres had something like this as well with Miller and Biron. The differences between these goalies are stark; obviously the right choices were made. However, I don't see the gap in quality being that different between Halak and Price.
I see Halak's playoff hot-streak as more of a one-time thing than an annual occurrence. He'll continue on as a decent goalie, but I don't see him becoming a game changer (like Miller or Nabokov). Like Sergio said, they got a decent return on him, so it's all good. They've got another great goalie prospect in Desjardins over here with the Bulldogs, so they needn't worry too much. Fix the defence.
With Price, the Habs have a young goalie who has shown glimpses of brilliance, despite having a horrible last season. Now he has to put it all together and much more consistent, and I think the renewed faith shown to him by the Habs organization will only help matters.
It's a second chance for Price: you could liken him to a hotshot kid who just got the keys to a car (the starting position) his parents (Habs) bought him for graduating and he got into an accident (a horrendous season). He's obviously going to learn from the accident, and the parents, being the faithful and encouraging ones that they are, give him the keys to his fixed car. The hotshot kid, now humbled and experienced, gets in the car and drives off. Voila.