Vegetables and fruits are full of vitamins and minerals and antioxidants, but their micronutrient content pales in comparison to organ meats. Generally, organ meats have 10-100 times more nutrients than muscle meats, and you'll see that traditionally, organ meats were consumed and prized. In TCM for instance, there's a belief that eating the liver is beneficial for your liver, the kidney for your kidney etc. I used to think it's bollocks, but now western medicine is catching up (yes, heh) and scientific research backs up that belief-- the animal's body tends to direct the right nutrients to each organ, so, for e.g. lamb's livers will contain many of the essential nutrients for your liver. 1 serving of liver has well over 100% of the RDA of vitamins B12, A, B2, copper, folate and (easily absorbable) iron.
It's kinder to the earth too, because if you kill an animal, you should make sure you appreciate the sacrifice the animal's made, and make use of the whole animal, not just the nicer/prettier parts.
Note: It's very important to get organ meats from animals that have been pasture-raised and fed naturally, especially because animals tend to store toxins in their fat and liver. Although, frankly, whatever meat you get should ideally be from animals that are raised properly. It really doesn't cost you more (believe me, I'm a stingy student surviving on a budget), as long as you you avoid the usual popular cuts and go for unpopular (but a lot more exciting and flavoursome) cuts or... offal!