I think that vegetarianism as an ecological goal is a very sound approach. I don't really try to get involved wiht the cruelty arguments- I think we should be most concerned about sustainability.
I'm concerned that meat farming isn't sustainable. The amount of land and feed that it takes to raise a cow could far more efficiently be used to grow soybeans, vegetables, and HEMP!!!
I think that among animal protein sources, yoghurt and eggs are AMAZINGLY nutritious and still ecologially sound.
While I absolutely LOVE steak (I made the bext ribeyes I've ever eaten this week for a special occasion), I consider it a bit of a treat, and try to use black beans, cheese, and eggs for my daily protein sources, with a bit of chicken and fish here and there.