Answer:
Cats are strict carnivores, so get all their nutrients from meat. Good quality wet foods are high in Protein and Fat, and because cats are strict carnivores, they use these two nutrients as their primary source of energy. Be sure to look at the ingredients - The best cat foods are the ones with a very high named meat content (labeled as Chicken, Turkey, Rabbit, Lamb, Tuna, etc.) as the FIRST, or first three, ingredients.
It is advisable to stay away from brands that include Corn, Wheat, Cereals, Soy and various Sugars in their foods - cats have difficulty in digesting these and do not provide any nutritional value to the cat whatsoever. Wet food with these specifications are much easier to find than in dry food.
The amount of moisture in cat food is also very important. Dry food contains no moisture, so is quite dehydrating. Cats are notoriously bad drinkers, even when they are thirsty. This is because they have evolved to get all their needed moisture from their prey (their ancestors were cats that lived in very dry and arid environments where water was hard to come by), so therefore have a low "thirst drive" and will not often seek out water on their own. This is a trait that has been passed down over the thousands of years.
Canned or pouched food has anywhere between 60 to 80% water. Seeing as in the wild a cat's prey is around 65%-75% water, wet food provides a cat with more than enough water each day.
Many dry foods and low-quality wet foods are often packed with carbohydrates - "filler" in the way of grains and cereals, none of which cats can digest or gain any nutrients from. Grain is used instead of meat because it is cheaper to produce and helps kibble pieces hold together. Cats need MEAT based protein, not PLANT based protein. Cats will often overeat on lower quality foods because they are not getting all the nutrients they need, which often results in obesity. Because kibble is baked at such high temperatures, all the "natural" nutrition is destroyed. Wet food isn't processed to such high levels as this, so most of the nutrition stays intact.
Lastly, it is not proven that dry food cleans a cat's teeth. Kibble is hard and brittle, so shatters at the tips of the teeth - providing little or no cleaning friction. Dental issues usually start under or around the gumline, so kibble is usually ineffective. Some cats don't even chew; they will just swallow the kibble whole. However, some cats will have perfect teeth no matter what food they eat, while others will not benefit at all.
You could feed both, but dry food only really serves as a convenience to us, and provides very little for your cat. There are some decent dry foods out there such as Applaws, Orijen and Felidae with a high meat content in them and zero grains, but even that will never compare to the nutrition of canned food.
For high-quality Cat food there is: Blue Buffalo, Felidae, Weruva, California Natural, Instinct, Prairie, Natural Balance, Eagle Pack, Wellness, EVO, Bozita (the canned stuff is 90+% meat and can be bought from zooplus.co.uk), HiLife (60% meat), Feline Fayre, to name a few.
Another Answer
There are a lot of great brands of food out there for your cat. It really depends on what you are looking for and what country you are in. Foods like Wysong, Felidae, Chicken Soup, Wellness and Taste of the Wild are all great foods. From what I've heard Evo is also good if your cat has diabetes. If you're just looking for an all around good food look at the ingredients. Foods without corn, wheat, gluten, by-products, and dyes is generally going to be a good food. Not all foods with All Natural are really all natural. You have to look at the ingredients to determine if its really good for your cat.
Another Answer
Feed canned or wet food to your cat. Dry food is not good for their teeth, but could also buy plaque control treats, or brush your cat's teeth. As far as normal diet goes, eating either wet or dry food will not aid in dental health.
I also have some suggestions on what food not to feed your cat. For one, there's Fancy Feast and other supermarket brands. These foods often contain lots of grains, coloring and a lot of salt. The salt makes your cat love his food, but it's not good for him. Also, food coloring isn't good for cats (or humans for that matter!). Your cats won't care about the color or shapes in his food, which is what this brand boasts.
Another Answer
The best brand of any kind of pet food is whichever food the animal has a preference towards and the food does not negatively affect the animals health. Obesity is also, as with any animal, a negative health result.
Additional information: I lost two cats to the poison cat foods. Before getting another cat I did a lot of research on what food would be the best and healthiest. I ended up at healthypetnet.com and purchased the canned food from them.
I even ended up buying their kibble for my dogs. The kibble that I had been buying previously had all the wrong things in it. It costs more than store brands but I know for sure that my pets are getting food that is not going to make them sick and is good for them. After all, they can't go shop for their own so it is up to me to get the best.