It really depends on so many variables; how many cats are in the household, do the cats share a litter box, hard wood or carpeted floors, availability of products, human and cat allergies to litter types, your personal preference, and most importantly the preference of your cat(s).
In the beginning, I used clumping clay litter. In my last house the litter box was located in the utility room which was adequately separated from the living areas of the house. The litter box was situated on a piece of outdoor carpet which did a good job of catching bits scattered by the cat and dust tracks from the feet. After moving into a smaller house with hardwood floors and nowhere to put the litter box that wasn’t within close proximity to the kitchen, I decided to look for better alternatives.
I have one cat and what I looked for was; something natural, sustainable, odorless, cost effective and didn’t require as much precautions or cleanup as clay outside of the box itself. Clay was just too dusty and wasn’t a good solution for me. I’m not saying clay is a bad litter option, but, if you only have one cat and don’t want to deal with the dust factor then you might want to give a natural litter option a try.
There are several options available. I opted for recycled newspaper pellets. There’s some brand names available, or generic store brands at an affordable price. I’ve had great success with ExquisiCat available at Petsmart. Again, this works well for a one cat family as you don’t have to change out the entire litter that often as long as you do a daily clean up. The newspaper pellets don’t have too much of a scent, they don’t track dust, and they’re totally sustainable. A fifteen pound bag last my cat about 2 months. Also, I only keep about 1 inch of litter in the box as I clean it out often enough that my cat has ample amount of litter at any given time to dig new holes and bury his business.