I have this sticker on my Bible, and I find it hilarious and wonderful.

Yes, I am a vegetarian.*
No, I am not anemic, militant, or a supporter of PETA.
Why do I choose to abstain from meat? Well, there are a number of reasons, but mostly it is because I believe that as a Christian, I am called to live a lifestyle that strives for justice. Now, I hate the thought of baby chickens, cows and pigs being slaughtered just as much as anyone else, but the justice that I'm talking about is more a question of human and environmental rights.
I
highly recommend
this video if you want to know more. It is a lecture given by a professor at Pepperdine that I came across on iTunes U. The first time I watched it, I was practically jumping up and down, because it pretty much describes my thoughts to a T (and much more eloquently than I tend to when people ask me why I'm veggie).
*For the record, I am not a full vegetarian, I am a pescetarian. Which means I do eat fish/seafood. Maybe I will get there eventually. But for now, it gives me a bit of flexibility when someone else is cooking for me, and is a convenient extra option for protein and omega-3s. (And, sadly, sushi is just so good... :)