I'm actually going to go with Chapter 2. Sure, it didn't have the emotional impact of chapters 3 & 5... but just something about it clicked with me. But then, I admit that I have a thing for campy horror movies, and Chapter 2 was definitely trying to mimic a campy horror movie. Plus, that last image of a beaten Andy St. John, on his knees screaming at Lee through the sounds of the storm, as his re-animated mother shambles over for the kill... I loved that.
I still wish I had the option at the beginning to NOMNOMNOM all of the food right in front of Lilly and Larry, though. Just, like... stare at them, never breaking eye contact, as Lee inhales all of their rations.