I am curious what the best protein shake is, and what is the difference between whey, soy and regular protein?

They are different based on their contents... a lot of them have bovine content.

There is another option besides those you mentioned. Since I don't personally want to eat animal byproducts or soy, I really like Vegan Protein powder by Natural Factors. Made from pea, brown rice, hemp and chia, and vanilla flavored.

Me too! YUM!!