Richtofen
I'm shallow and I want my not-zombie Nazi, damnit! Original four > Extra characters, even if playing as Buffy is kind of hilarious.
Good to know I won't be throwing money at this one!
(Though on that note; we all know it's just the map pack now, but was anyone else originally hoping it /was/ a game? Would you buy a Nazi Zombies-inspired video game? )