It may be because of my recent enjoyment of it but.. I'll say Portal. Specifically Portal 2. Some games can't even make humans sounds emotional. This one has robot/computer voices with obvious sarcasm, fear, anger and sometimes...loveeeee
Alundra.... While the first game had a very interesting plot and great character development, dreams, vampires, drama and all in one town! The second game went with pirates and puzzles. It was terrible (>_<)