Cats are obligate carnivores, meaning they get 100% of their nutrition from protein (meat, fish, poultry). Also, cats tend not to drink much water; in the wild, they get all the fluid they need from their prey. So moist / soft / wet food should be a regular part of the diet.

When you feed a high quality food, there are no hairballs. Hairballs are NOT normal, though most house cats have them, because of the poor food they eat.

High quality grain free foods: Earthborn Holistics or Taste of the Wild, for dry; and Tiki Cats, Weruva or Fussie Cat.

You can learn a LOT about cat foods here: http://www.petfoodratings.net/cattable.html