Glad to hear that you are enjoying the site, and kudos to you for providing a loving home for these five kitties.
As to your question on the cat foods - the first thing I would say is that you are looking in the wrong place for a "good" food.
Grocery store brands are all lower quality.. not an optimum diet for nutrition.
The first three ingredients are the all-important ones.. and corn should not be one of them.
The pet food stores are the best resource for the best foods..of which there are many excellent brands to choose from.
I would definitely agree with getting them off the Cat Chow... just a gradual switch of introducing the new. Iams also is a food I would not feed myself.
If you are feeding dry only, I'd also suggest "some" wet food be included regularly too - to avoid the UTI issues that can occur from an all-dry diet.
If you browse over the Cat and Dog foods board here,you will see that there are many brands that are highly reccomended and very good foods.
Now, I undertand what you are saying about the cost factor.. some of these foods are expensive to buy, and with 5 cats... a real consideration.
The choice has to be a realiistic and feasible one for your budget.
What you want is the very best, most nutritious food that you can you possibly manage financially.
Doing research online about cat foods, the various ingredients.. and then comparing with the products, you should be able to make a dietary improvement that your five kitties will greatly benefit from over the long haul.
I have 3 cats, and buy the large size of Felidae cat food at the pet store.. and freeze it. This cuts the cost considerably.
Mabye something like this might work for you also.
Good luck with this, and yes.. would also love to see pics of your sweeties!