It's an easy decision. Iginla is the best player in the NHL, and the offer would have to be huge to even get consideration. The fact is that the Flames aren't in a rebuilding mode, they are an elite team. When the NHL comes back, the Flames will compete for the cup, IMO. There is no point in trading him.
Once again, people like you are looking at the "now" and not taking into account the future as well. In 2-3 years, when Phaneuf, Regehr and Leopold are all hitting stride..those three will command some big bucks. Also, if Kipper keeps playing as well as he did last year, his salary will be quite high as well. The Flames are a team and if Iginla has to be traded to keep together a core of players that overall betters the team, I think Sutter would do it. The Flames are not just Iginla, there are 20+ guys on the team. Yes, Iginla is the best but he doesn't stop pucks in goal or play defense like Regehr or Phaneuf will do for the Flames in the future. If the time comes, guys like Phaneuf will be the new face of the team.