While not killing animals seems to be the popular understanding of why people choose not to eat meat, it isn't the only reason. I've recently drastically cut down my meat intake since returning from a trip to SE Asia. The trip highlighted for me the damage we are doing to the environment, initially when I noticed the ridiculous amount of bottled water I was going through in order to not get sick. This led me back to Hank's "Eating Man Meat" video and, along with an irrational fear of being served dog meat in Vietnam (thanks a lot, Lonely Planet), has brought me to the point where I only eat meat for special occasions or not to inconvenience people.
I am now eating about one or two meals containing meat a week and I feel like I can sustain it. I was vegetarian for a while in my teens but at some point I just started eating meat again. Now, I feel good about doing less damage to our environment and don't have to worry about meat cravings because I know if I really want to eat ham and turkey at Xmas I can and I won't be falling off the wagon.