I really like that one two-second section of the intro in KHII when Sora's fighting Riku/Ansem/Xehanort's heartless. I don't know why, but I just LOVED seeing a part of that scene in better graphics. I also loved that cute little moment where Roxas said nobody would miss him if he were gone, and Axel, after he was out of earshot, said to himself, "That's not true..... I would." I also starting shedding a few tears at that part where Sora found Riku and then just collapsed and started sobbing. Seeing Sora cry was just a little too much for me. Although this was so amazingly insignificant, I really loved that little moment in this one cutscene in Agrabah (KHI) where Sora puts out his arm to protect Goofy... No idea why, but I always loved that.
I never noticed this until after I played Kingdom Hearts II, but in Neverland, close to the end of the game, Sora says "You're stupid!" to Riku and his voice cracks. Then, of course, in Kingdom Hearts II, out of nowhere his voice is way lower. Hooray for puberty!
(And why the heck does my stupid computer keep posting everything twice? I swear I'm not doing that on purpose. Does anyone know how to delete a post?)