I can't really decide on this, but it's got to be one of my buddies. Kenny, Ben, or Doug. Kenny of course died (for me) in an alleyway saving the one person in the world he used to hate the most. Ben. And I thank him (Except for the dying part) for putting the kid out of his misery, and also restoring his humanity.
Then there's Ben, and this isn't exactly a death though. I saved Ben of course, but when he was dangling there, and telling me to go on and drop him so he could save the others some time, I knew that he thought the only way he could help was sacrifice. I agree with him on most things, but not on this. But I honor him for his bravery.
Doug was a funny character who thought he couldn't do anything without a couple batteries and spare parts. I guess he became a good friend of Ben on that walk back to the Motor Inn in Episode 2, because he saved Ben's life. The thing is, he pushed him out of the way, not pulled, so he got hit by the bullet. I would vote for Doug, but then again he died by accident, even though he did a brave thing.