The twins' reunion in Frost Bites, after Edgar had briefly thought Ellen dead. For some reason, the text doesn't mention the hug they share, but an illustration shows it, and it is glorious. Destruction is raining down around them, and they don't even care.
Their reunion in Split Ends as well, although the dramatic tension is considerably lightened by their exchange beforehand.
Heimertz and Dahlia's wedding in Hot Air. These two went through a lot to get to this point.