Keep in mind that my cats don't use the litter box often (they're not bad, they just prefer to go outside)! Didn't realize how bad that sounded at first!
Anyway, I use the Tidy Cat regular litter, not the clumping kind. Some of the others had such a strong odor that Mimi hated it. I get the kind that is for multiple cat households and since I don't have to change it often, it is a very inexpensive alternative.

Logan