I enjoy cading up and defending a house as a survivor or breaking into a house with an otherwise "perfect" cade on it as a zombie. Its pretty satisfying either way, almost as much as a high score.
I do enjoy my games with lots of teamwork though, especially on the survivor side since its difficult for them to win. Maps like shreddingfield are my favorite because it takes quite a bit to get through as a team. I think I've only won that map twice though, lol.