After the infamous "G-Man vs. Nihilanth" thread here comes the expected (I guess it is...) sequel!
New say, wich one of the big endgame bad guys did you liked more? Is it dr. Breen, with his white beard and persuading smile or good ol' Nihie, with his, erm, baby looks?
For me personaly, Breen rocks. He was administrator at Black Mesa and then he went up the career ladder, becoming something like governor of Earth. And he has great speaking style (almost as good as G-Man's vocabulary!).