Knew Garp was once Aokiji's mentor. Always very similar morally. Well done fight between the two. Very emotional, and Aokiji did a nice job in trying to hold back Garp's ACoC, even without having it himself.
Thought for a while now that, if Shanks is going to be Luffy's final test (which it looks like more and more), and Luffy ends up fighting Teach before Shanks (which it looks like), then the catalyst would be kidnapping Nami (Teach is well informed and may have sensed something about her when they first all met, or just id'd her as a mark to lure Luffy), or holding Garp hostage in the event Garp lost on Pirate Island. Could be a combination of both that spurs on their blood fued.
Great chapter after the break.