I am not a nutritionist, but I don't think there is any "best" vegetable. They all have different properties and some have more of a certain kind of vitamin or mineral than others. My personal favorites are tomatos, spinach and onion. Vegetables can be grouped however. Green leafy vegies, like spinach, have a lot of good cleansing properties, high in iron and vitamin C. Orange and red colored vegetables are high in caratanoids which is an antioxidant and are high in vitamin A. Vegetables can taste great, it all depends on how you prepare them and mix them with other ingredients. I am a vegetarian and have been my whole life. I think it is the best diet for me personally.