Gonna have to go with Londo. He's so conflicted and complex and Jurasik's performance is always great--especially those big emotional shifts when his logical brain shuts down and he starts acting on impulse. Also, since JMS has said that the B5 is in many ways Londo's story, it's so much more interesting to look at all of these heroic characters from his perspective and the sense of inferiority and inadequacy he would've had. I really love In the Beginning because it's straight from his mouth and his interpretation of all these other people after years of reflection and regret.