1. 24 - Curtis Manning
Jack Bauer's track record with partners was never great (hell, neither has his track record wit his loved ones) Still, as Jack's partner through seasons 4 & 5, Curtis was one of Jack's better partners. He always kept his cool, and as per usual for a good CTU agent, could handle himself pretty well in a fight against the bad guys. Unfortunately we didn't learn much about Curtis' personal life until season 6, but by then it was too late. Apparently, a former terrorist named Hamri Al-Assad who was helping CTU track down the real bad guy had actually been responsible for killing several of Curtis' troops when he was in the Middle East. Curtis was understandably angry at having to work with Assad, but couldn't set these feelings aside for a couple hours, so he decides he's going to kill Assad. Jack, having told the president he would protect Assad, is forced to kill Curtis by shooting him in the neck. He's devastated afterwards, even telling Bill Buchanan he's quitting. Here's the problem: that's the extent of Curtis' death. There's nothing else. Several minutes later, the nuclear bomb is detonated in Valencia, propelling Jack back into action. Curtis is only mentioned a couple times in the rest of the season, and he's never mentioned again. At least when Jack killed Ryan Chappelle in season 3, it eventually helped them catch bio-terrorist Stephen Saunders. Curtis' death served no purpose, especially considering Assad would be killed several hours later. I understand the world of "24" is a bloodbath, but Curtis deserved as least a heroic death.