I sort of read Jack's internal struggle with the heart also going back to his father--He said something to the effect of, "It's not about living forever, it's how you live with yourself forever."

And Jack couldn't have lived with himself if he'd let the whelp die like that, I bet.

I especially thought the juxtaposition of Davy Jone's comment to Jack, "You're a cruel man" to Davy Jone's cruelty of killing Will--and twisting the sword--TWICE--to make it more painful. He didn't have any reason to kill Will at that moment--it wasn't going to change the situation or his position--he just DID it to be cruel.

I'm feeling better watching it the second time. I'm still pissy about the ten years, but I'll get over it.

I suppose it is a testament to the skill of the writers and actors that I care so much about the ending of a pair of fictional characters in a summer popcorn flick.