I understand both sides to this subject.
It must be terrible for those in the situation where a certain organ is desperately needed, only to be denied because of a lack of organ donors. Especially for innocent children. Just one person could save the lives of up to 10 people and improve the lives of dozens more.
But I totally understand the other side. Saving the life of a meat eater means more animal deaths and cruelty.
In the end I think it comes down to personal preference. It's your body, your organs, what you want done with them is your choice.
I've yet to decide whether to be an organ donor or not. Whenever I think about it, I go back and forth in my mind.
Did you know in some cases peoples lifestyles are changed completely by receiving an organ? It's believed that organs, such as the heart can actually store memories. It's known as cellular memory.
There's info about it here:
http://hubpages.com/hub/Cellular-Memories-in-Organ-Transplant-Recipients
"Common quirks recorded have been changes in attitude, temperament, vocabulary, patience levels, philosophies, and tastes in food and music."
Imagine if your organs could turn omnivores into veg heads!

But even still, I remain undecided.