It really depends on your budget and what you have near you. What do you want to spend each month on cat food? What is near you that sells pet food (independent stores, feed stores, petco, petsmart, grocery store?)
If you aren't feeding any wet food, I would do my best to add wet food to their diet at least once per day. It doesn't have to be the best quality wet food because any wet food is better than no wet food at all. I would try the following relatively inexpensive wet food brands: Authority (PetSmart), Nutro Natural, Nutro Max, and/or Meow Mix. Wet food is important because cats aren't naturally thirsty and don't drink enough water. Their water mostly comes from their diet (mice, etc.) and when they only eat dry food, they live their lives in a constant state of dehydration which can create health issues later on. If you can afford a water fountain, they are great for getting cats to drink more water.
As for dry food, you should be pickier about what goes in it than you would be with wet food. While Meow Mix wet isn't too bad, Meow Mix dry food is basically junk. Iams isn't great either last time I checked. Most 'grocery store' brands are not ideal. They are comprised mostly of filler ingredients that aren't nutritious.
The more affordable dry foods I would recommend:
- Authority (PetSmart)
- Diamond Naturals (can find this at feed stores usually and small independent pet stores)
- Natural Balance (PetCo & feed stores)
- Nutro Natural (PetSmart/PetCo)
- Nutro Max (PetSmart/PetCo)
- Chicken Soup (can be found at feed stores and small independent pet stores)
Remember that just because a food is more expensive, it doesn't make it a better quality food. For example, Science Diet can be pretty expensive but the ingredients are not great. Diamond Naturals is relatively cheap yet the ingredients are good.
Other dry foods I would look at:
- Royal Canin
- Taste of the Wild
- Solid Gold
These links might help:http://cats.about.com/cs/catfood/a/canned_food.htmhttp://cats.about.com/od/dryfood/tp/premdrycatfood.htmhttp://cats.about.com/od/catfoo1/tp/tpcannedadult.htm