Quite a few but the one that really sticks out is Akira, having managed to overcome the vampire lords' assassins, reaching where Mina and the lords are before the deadline of their bet (the lords were wagering among themselves which of their assassins could kill Mina's "dog" and return first). Having expected Akira to die (not surprising since they hate werewolves) the looks on their faces are priceless. Even better, the one that gave Mina the "chastity test" ends up dusted after foolishly trying to rush Akira. And of course the salute of the wolf corps as they take Akira to be treated.
In Volume 13, perhaps the crowner of the series... Lords Scott, Antonio, Ernest, Edward and Connery make a stand to rescue Mina and Akira from Rozenmann's army, laying down their lives. All of them die with smiles on their faces, having devastated Rozenmann's army, rescued their lady and even destroyed Rozenmann's pride and arrogance, taking his castle with them. Mina's tribute to them is to cut her hair and release the strands into sunlight, creating trails of fire to honor her guard. It'd be a tearjerker if it wasn't just so damn badass.
The rescue of Mina in volume 12. All of it. The best part being when Akira and Mina are escaping, and Rozenmann and his men can only watch from the window. Mina smiles at him, then flips him off.