Nappies, also know as Diapers in the US.
I choose to use a combination of Cloth and Disposable nappies for a number of reasons. I use Bamboo Flats (think terry toweling squares) with or without a cover at home, and disposables or All-In-Ones when we go out as they easier to fit in the nappy bag.
I tend to use the Flats over the fitted All-In-Ones (Modern Cloth Nappies) as they dry much faster, can be bleached if needed without destroying the elastic, and can be chucked in the dryer without affecting the waterproof layer.
There are 3 folds I use.