Hi Want To be Hindu,
Somebody once said, "If we don't stop killing animals, we won't stop killing each other" this sums up my views on vegetarianism. The propensity that exists within us that makes us kill others is the same propensity that makes us crave meat. It is a part of our evolutionary history, when we did need to subsist on meat, but this was also when we were violent and predatorial creatures and barely had any moral understanding. So to answer your question, no you cannot live a moral life and still eat meat, because you keep that primitive propensity alive. In Yoga this is also reiterated, it is categorically stated that one will not reach higher stages of spirituality if they continue non-vegetarian lifestyles.
A few have asked why are we omnivorous then? We are omnivorous because we are not instinctual creatures, we have rationality, which means we can exercise far greater choice than animals. We can choose between good and bad. The fact that we have this choice makes us think we are omnipotent and do anything we like. That also means declaring yourself as hegemon of the world and killing animals for ones enjoyment. Many of us take great pride in our choice, we declare, "It's not bad, if I have the option to do it" or translated in terms of the context of this thread, "I am omnivorous, which means I can eat what I want" On the surface it does seem as if we have free will and we are living in a chaotic univese, but go deeper and you realise that there are deterministic forces and fundamentals laws operating, which will make the outcomes of choices we make beneficial or harmful to us. Meat-eating is one of the choices that are harmful for us and this is born out in the amount of disease associated with meat-eating, salmonella poisoning, mad cow disease, and the ecological imbalance that is taking place in the world, but the greatest harm is subtle, it affects ones intuitive abilties and prevents access to our higher mind.
Non-vegetarianism is a destructive activity and emphasises a regressive part of us and thus can never be a part a spiritual and moral life.