Personally, having been the one to go through and write them all, it's hard to pick a favourite. Basically, I despise chapters 1-10, and the rest are okay. But I guess if I had to pick... I'd go with Chapter 20: Midnight Mischief Managed, because it was the one where everything kind of came out in the open, and I like mushy Lames (man, that name is pathetic) endings. Plus, I got to torture Peter a lot in that one. What more could you ask for?