I read in this book The Organic Garden Green and Easy by Allan Shepherd that in the US it is fairly common practice to go into the streets and kidnap leaves piled up for removal by the council! Leaves are so easy to compost! He says to just put a section of chicken wire around four posts and throw the leaves inside. The wire holds the leaves in place and they rot down quickly and look like a very fine soil when fully composted.
I get an endless supply of free leaves from the tree outside my terrace, which also cools the room near it. It becomes like an air conditioner. And then I just have to collect all these leaves and compost them. Often I put a huge pile of them inside a pot, then layer it with fresh red mud and home made composted soil, and plant an ivy or a creeper over this. It becomes a tiny leaf garden and as the plant grows, the leaves get composted deep down below!
Leaf mould also adds depth to top soil. You can also just pile the leaves around existing plants and let worms and other compost creatures do the rest, says this book. The leaves also act as a mulch, keeping them moist and reducing your need for watering the plants.