As you've observed, there is a dazzling array of dry cat foods, from very inexpensive store brands to expensive premium foods. The national brands are most consistent; store brands tend to vary a lot more, although they are usually made by a national brand on contract.
The best foods have the most meat in them, and your cat (like all cats) is a carnivore. That means he has to have meat. Depending on how much you're willing to spend, you can find a real range of quality of ingredients.
There are foods that are formulated as kitten food and "mature" foods, indoor foods, and hairball reducing foods. These have mostly to do with how much fat or bulk is in the food.
When it comes to treats, etc., we have one cat that loves anything like that, and one that won't eat any of it. Those who are unacquainted with cats may be surprised to hear that cats are individual in their tastes; anyone who has had more than one cat knows the truth!
Now...I would rather see your kitty happily eating the cheapest store brand kibble than being wild on the street or in a shelter cage or being put to sleep. But a good food will have a minimum of excess grain added as bulk, and your cat won't have to eat as much of it to get his required nutrients. You will find some recommendations here for foods you can only get online, etc. But such foods as Purina One or various other "upscale" foods are easily available and perfectly acceptable, in my view. In fact, my brother has fed all his cats on regular old Purina Cat Chow, and they have all lived to ripe old ages; he has two that are 15 years old right now, and doing fine.
I have one fussy cat, and all I can get him to eat is Hill's Science Diet, which is available at most pet stores. When we got him from the shelter, he was quite underweight, and it took us a while to get him eating well. We give him a daily treat of wet cat food, Friskies sliced meats in gravy. It's cheap stuff, and he'll only eat about a teaspoonful, but he does enjoy that much.
You do need to watch that your cat doesn't get overweight. Some cats can have food available to them all the time and never have a problem. Some need to be fed a measured amount daily, and no more. You can judge if your cat is getting overweight; you should be able to just barely feel the ribs along both sides of his backbone, without them being too easy to feel. Too much weight contributes to a lot of health problems in cats...just like in us!