Killing animals for food-
If I was starving for food, and I saw a tasty, fat, happy cow walking by, and I had a weapon....yeah that cow is dead. xD I guess in a larger sense, I have always felt that the life of a human being is more valuable than the life of any other animal. Hence, I don't think I would think twice about killing an animal if I needed to eat. If a wild animal was hungry to the point of death and it was a carnivore (or another animal, for that matter?), I think the question has to be raised: would this animal think twice about trying to kill and eat me if it was on the brink of starvation?
Killing animals for medical purposes-
Once again, if I myself or one of my loved ones were ailing and I saw an animal I could kill to obtain the cure, I don't think I would hesitate in delivering my death blow. I can see how this might be seen as selfish, but I really do value my right to live and the right of other human beings to live over that of a wild animal.
People dying in War
I think as long as there are conflicts of interests, there will be war. The soldiers that are sent off to fight these wars are trained to be merciless towards their enemies. Every soldier wants to stay alive. I think the idea here is, "I don't want to kill you, but if I don't kill you, you're going to kill me, and I don't want to die." Hence, I think that killings in war are almost always in a way self-defense, and hence justified.
Getting an Abortion-
I can see how this might be justified, in the case of rape or sexual abuse, but I disagree with having late abortions/certain forms of abortion which are cruel and unnecessarily painful.
Assisted Suicide/Euthanasia-
I think this really depends on the situation. If the other person is really suffering and has no chance of recovery, then maybe.
Death Penalty-
The way I see it, this should only be applicable to cases of straight-up murder, the idea here being, "You took away someone else's chance to live, so your life is forfeit. Equal."
Self-Defence-
I think this is completely justified. I mean, if the other person(s) made the choice to kill you, and you have no means of escape, are you just supposed to stand there and let them kill you?
Suicide-
I don't believe this is justified at all, and is a very selfish choice. There are so many options for help in these situations, and by making this choice, you are hurting so many people in ways you can't even begin to imagine. Definitely a no from me here.