I love using the clumping multi-cat version of World's Best Cat Litter, though it's a bit more expensive. It's corn based, natural, easy to clean (unlike heavy clay litters) and you can even flush it (I don't). The litter lasts and lasts without smelling bad... longest lasting litter I've ever used. There's no dust, very good odor-control, and it's pet, people and planet friendly. An all-round winner!

As a bonus, this is the recommended cat litter if you foster kittens - they can even eat it and it won't kill them. I use this exclusively every time I foster cats.