So what I've gathered this far is nobody would trade anyone on their team that has some semblance of value for anything other than an overpayment....seems realistic.
No untouchables on the bruins, only players harder to obtain than others, some that's likelyhood of being offered fair value in return for is a lot lower, I would say the only 3 players in the NHL I would see being untouchable are Crosby, Malkin, Stamkos. I think we all know the backstory to why Gretzky got traded, in both cases, (Money problems (can't trade a player for cash anymore) and a shot at a cup, not a current problem for any of the 3)
This, I would not trade Giroux for anyone in the league straight up. You can't beat the value he gives you at the cap hit he costs along with the eladership he brings.
Malkin or a healthy Crosby would be the only ones for me, but they fit the same category for Pittsburgh. Stamkos is close, but if forced to chose, I would keep Giroux because I want to see what Stamkos can do once MSL isn't on his wing.