I love slate! Well, I love most stone, but slate is so versatile. And cheap, sometimes even free. It can change the whole look of a garden, as a path, or a low wall, or a patio. Even when found in the woods, it is usually quite flat, so it is ready to use. Sometimes I buy a box, 5 square feet for less than $10 in Home Depot. The pieces sometimes break a bit when walked on, but that makes it look more natural. I set the pieces in mulch, instant patio.