Yes!!! @ the ending comment.
Did they choose that ED song because the story ending had that (fantastic, awesome, orgasmic) part? Or did they put it in the anime because of the (fantastic, awesome, orgasmic) ED song? I mean, they even mentioned the Summer Triangle in the show, which is a central theme in the song.
That episode made me laugh and cry in the span of a few minutes. The words that came from Hitagi hold so much more weight because of her character. She is tsundere-chan after all, with tons of actual pride to boot, so her lines pertaining to giving her everything to Araragi was just so powerful.
Her harsh nature has finally been rounded out with the character development in this episode. She plans to give Araragi everything, even exposing her weakness and lack of confidence as she enumerated all that she can possibly provide, an incredible feat for someone like her.
I fear that trying to analyze the awesomeness of this episode (for me) is simply futile, so I will end it with I love Hitagi-san.
EDIT: I also loved how cute Hitagi-san was with her plan of using her father to force Araragi to call her using her first name. I have come to dislike or get bored of tsunderes as of late, but this was just cold and fantastic.