For me, it would have to be these (in no particular order):
Aveline's The Long Road quest. Everything about it was absolutely hilarious, especially with Isabela there. Aveline was just so bad at wooing Donnic. My first Hawke flirted with Aveline every chance I got. He looked so cut at the end when Aveline wouldn't give him the time of day, despite him being significantly more interested in her than Donnic - Hawke's expression was priceless at the end.
When Merrill goes to the Hawke Estate for her kissing scene. I love the way that scene was choreographed. Merrill turning her head away conflicted, then Hawke grabbing her chin gently, and turning her head back to face them. Male Hawke's VA did the line "Merrill." so very well, and the female voice in comparison was terrible - and I'm totally unbiased between the two voices. The female version sounds like Hawke was asking Merrill a question, rather than firmly trying to get her to face Hawke in a, "don't be silly, I know you want this as much as I do" kind of way. The way the male voice does it fits in with the assertive action of physically grabbing her chin, which could be seen as crossing a line, especially since Merrill was showing signs unwillingness.
"Hanged Man." "Even I know that." The scene where Seneschal Bran pretends not to know about the Hanged Man, was just hilarious. Definitely Sebastian's funniest line in the whole game:
Bran: "But where you'd find swordsmen so eager to sell their honour for gold, I'm sure I have no idea."
Anders: "The Hanged Man."
Fenris: "Hanged Man."
Sebastian: "Even I know that."
Hawke is turned on by crazy. If you romance Anders, Varric starts a conversation in Act 2 or 3 where he expresses concern. He says that Anders is crazy, and my sarcastic female Hawke had a hilarious response:
Hawke: "In all the time you've known me Varric, when have I ever given you the impression I was turned off by crazy?"
Varric: "Hmph. Good point."
It was particularly funny for me because she tried to sleep with Isabela, Merrill AND Fenris, in addition to Anders (she only failed with Fenris). She hit on everyone she could possibly flirt with in the game, so I thought it was a very fitting response.
Aggressive Hawke stabs Javaris in the back. In the last scene you have with Javaris, you can stab him when his back is turned. This one is very hard to describe in words, you really need to see what happened. My aggressive Hawke's head took up much of the screen when she turned her head a little bit in Fenris' direction, as if she knew what his reaction would be. Without words he shook his head, and I'm not entirely sure why he did it, but to me he was either thinking "What you did was awful, Hawke," or "Tsk, tsk. What a foolish and rude dwarf." It was just a satisfying scene involving aggressive Hawke and the rival Fenris romance, even if it was a bit confusing.
Raiders on the Cliffs. That whole side quest was really good, especially with Izzy and Aveline, but my favourite part of it was what aggressive Hawke says when they try to get the city guard to fight with Hawke's party:
"Anyone who leaves, is a deserter. And we all know what happens to deserters..."
I loved how menacing Hawke is there. Unfortunately for me, the audio gets cut off half way through. =(