IF the man was in custody and someone walked up to him and put two in the head, that's just plain wrong. It doesn't matter who the person is... However, if he was posing any kind of immediate threat and he somehow got two in the head. That's just the way the cookie crumbles... we'll likely never know the exact situation.
Same goes with the NATO bombing though there seems to be more and more grumbling about that one and it is starting to look more like an attempt at regime change than the defense of lives. Not that it would be a great surprise... In any case, there can be all the yapping in the world... Might is right and no one has the means to really do anything about the actions of the US and its allies and it all comes down to political power plays.
Seriously, who would stand up to defend Bin Laden except the fanatics... However, I don't believe that offensive actions like bombings are necessarily productive in the long run. It feeds the fire of hatred and only helps in digging deeper trenches between cultures. I understand revenge on an individual basis but it would be nice(though very naive) to see the state rise above that particularly when said states pretend to cloak themselves in mantles of freedom, democracy, rule of law etc...
Anyway, I've always felt that these principles apply far more to their own citizens and ALL nations are quite happy to take shortcuts when it comes down to protecting their own interests even if it's at the expense of people of other countries. Very simply put, an innocent american life is worth a lot more than an innocent libyan life in the eyes of America and you can substitute pretty well any nation in this sentence and it will still be fairly accurate.