What are they? Well... that depends - are we going by the play or the book?
When it comes to being "canon" I go to the book first. But that's only because when I expand on Pan, I'm doing so in novel form.
In the play, he invokes his Alma Mater: Floreat Etona
In the novel, having goaded Peter to kick him rather than stab him:
"Bad form,” he cried jeeringly, and went content to the crocodile.
Now since the book came second, one must think that Barrie consciously changed his mind as to what the pirate lord said. I'd imagine that must be the case, since in the novel the whole good/bad form is played up to a large degree, especially concerning Hook.
However, when checking into the last time he revised his own story (a la his unused screenplay) Barrie again uses Floreat Etona. As a second however, though, it is not written with quotes around it as are the other bits of dialogue (on the screen, as it would have been a silent movie.) Thus, we can see that it is definitely important that Hook be associated with his school as he comes to his end.
So perhaps we can reconcile this non-threatening incongruity in this way: Hook said "Bad form" and thought Floreat Etona.
Also interesting to note the contrast of what Peter Pan said as his last words when he thought he faced death:
To die will be an awfully big adventure.I say interesting because either way as per Hook's last words, he's being childish. That is... with his Alma Mater quote one can argue he's longing for his boyhood school days. With his other words he's reduced to mocking his foe, as a child might do. Pan, on the other hand, seems to face it bravely and with a very mature philosophical spin. In Hook's defense regarding the screenplay: He does walk the plank with commendable bravery (while thinking of his Eton days) and dives straight into the crocodile's mouth.
Just me over-analyzing again. In either case, at least ol' Pirate James knew that he'd be speaking his last words and could choose them. Someone else I'm thinking of didn't have that luxury! What also comes to mind is that if we're dealing with the alternate timeline of the Barrie universe, a la the Neverland of author Andrea Jones, what would Hook's final utterance be then? (Just fun to think about - this is in no way meant as any kind of indication as to upcoming events in her books.)
And that's the last word on the last words.