1. Dumbledore. Sure, he was dying anyway when he had Snape kill him, but all the same...
2. Dobby. He deserved to be free for much longer.
3. Sirius Black. He had so little time with Harry, and none of it as a free man.
4. Fred, from "Angel." Gah, that was a sucky death; to be turned into a demon!?! Grr.
5. Cordelia, from "Buffy" and "Angel." Her character deserved to continue. Gah, dying of childbirth-induced coma. Sucks.