War sucks, but it's very necessary. Animals are motivated by survival instincts, and survival instincts naturally motivate greed- resources like land and money are things that change hands during war, and I don't ever see that stopping.
As [MENTION=11]Devin[/MENTION] said, war motivates advancement. We wouldn't be where we are today technologically and socially without it.
I don't like war any more than the rest of you, but it's a fact of reality, unfortunately.