This entry makes the list with a heavy heart.  Any true 24 fan was devastated when Jack decided to shoot CTU Agent Curtis Manning in the neck in order to save a a terrorist.  The government needed the terrorist and Jack could see that Curtis was willing to not allow that to happen.  The shock value isn't the only reason this kill makes the list.  It's an amazing precision shot.  Jack is an expert marksman, and he proves it by killing one of one of his CTU brethren.