it's all about fiber, man. Fiber.
gots ta poop.
the v8 ads make me mad. sure, you might get your daily serving of vitamins by drinking it but eating veggies is more about the fiber, not that vitamins. take a supplement if you're worried about vitamins (with food, of course!)
dark green leafy veggies like romaine and stuff like that are better. don't waste your time with iceburg lettuce - it's bad for you.
i live for broccoli but i'm not sure just how good it is for you.
tomatoes. peppers. eggplant. zucchini, squash.
fruits are good but be sure you take care of your teeth cuz of the sugar. apples make your teeth feel clean after eating them but that doesn't mean they are. and don't eat oranges or acidic stuff after brushing your teeth.
Generally the american diet isn't lacking in vitamins. what things you want to eat would depend on your specific health needs. like, I've got arthritis so I eat food that help keep my joints working.