What I learned in the class about our area is you really want to plant things that provide color or texture for more than one season. I was struck by this idea as I did planning and planting in my gardens. Now, ten years later I can take pictures this time of year and be convinced that I did create color in my garden based on the information I gleaned from all my sources.
Hostas provide bright color in the fall as the leaves turn yellow. 
Maples create different leaf colors depending on the type. This one in the backyard is a lovely mix of color right now, especially when the sun shines through the leaves.
The maple leaves out front create a lovely yellow hue.
Our red rose illustrates that summer isn't over yet, especially with two buds sitting side by side ready to bloom.
Even lilac leaves turn a distinctive color in the fall of the year. As some plants turn they are showy and add a focal point to a fall garden. Others are more subtle, but help create that mosaic of color and texture as they blend together to make autumn so glorious.