As for myself, I'm torn at this moment. John Morris knew from the start he would die as a result of his quest, but went ahead with it anyways. That kind of resolve is unmatched, but then again, Alucard had to kill his own father, who, while depraved and twisted, still loved his son, and Alucard still loved his father. That would have been incredibly hard for a son to do. So it's a toss up.
Also, Richter's on my top 5.