Well he's currently on pace for 58 points, and he plays 24+ minutes a game in all situations (PP and PK). He isn't very flashy, but he's been about as reliable a defenseman as you could be. He just doesn't make mistakes. Compared to Redden and Meszaros last year, he's been outstanding.
I think the asking price would start at a first round pick.
Agreed, outside the northeast and to a team more on the fringe he fetches a first and maybe a prospect like Ted Ruth or someone of that ilk.
If the B's want to acquire him, I think Stuart and a first is closer to the price - from a division rival, they'll probably want an NHL ready defenseman in return.
If the Bruins were asking, the Sens would probably want a young puck mover in return. A Hunwick or Lashoff would probably be asked for, but I don't know how willing Boston would be to part with them within the division.