Moira from Fallout 3...or maybe Ashley from Resi 4.
Moira; I blew up the nuke in megaton for the sole reason of killing her off in an OTT manner.
To my severe annoyance she is the only survivor (Not including the 'Megaton survivor' NPCs.)
As for ashley, everyone that has seen resi 4 knows the annoying cry of "Leon Help!" which for me was followed by the grinding of my teeth.
Worst part is if you make the effort to walk around a bear trap, she'll happily hop right in there, draining most of her fleeting health. If not killing herself off, since in the harder difficulties a strong breeze proves fatal to her.
All i can say on Ashley is thank god for the suit of armour she got on the PS2 version and Please capcom, don't put her in any other games, ever!