Carnation, my niece had a fall wedding in Illinois and my sister (in true Martha Stewart fashion) picked leaves off of red "burning bushes" (I'm sure YOU know the correct scientific name of this bush) and ironed them in wax paper and sprinkled them around the reception on tables. They were very pretty.
I'm in the midst of autumn wedding planning...and I must say, it's kind of a great time to get hitched because you can get lots of the little things you need after the post-wedding season rush for a discount.
And you've got a lot of colors to pull in: browns, reds, yellows/golds, oranges, etc.