Composting fallen leaves is a wonderful way to dispose of them in an environmentally conscious manner.
Mulching the leaves into your lawn is also easy to accomplish by mowing right over the leaves where they sit and allowing them to integrate into the soil.
This removes the matting-down effect in low-lying areas where damp conditions tend to persist, and provides your lawn with a healthy new layer of nutrient-rich loam that will keep it healthy during the upcoming growing season.