I planted a 5 gal. fraxinus pennsylvanica (Green Ash), a fast growing native, which is growing by leaps and bounds. Its a good tree because its a vigorous grower when young and although it hits 50-60 in height and 20-30 in width at maturity, it won't displace your concrete sidewalks. Despite its fast growth rate, candidly, I wish I had bought a larger, tree. Then I'd have a pretty substantial addition in just a couple years time.
A quercus palustris (Pin Oak) is another fast growing native that will grow larger than a Green Ash (add 20 feet to height and width). Like a Green Ash a Pin Oak does not have an invasive roots system, so it won't displace your sidewalk, either.
Both trees transplant easily and tolerate a wide variety of soil conditions.
The native tulip poplar is a handsome tree, too. A fast growing hardwood, VERY tall (over 100 feet, I think). People say they're messy, but that puzzles me... the one we planted doesn't seem to make a mess. It was about 10 feet tall 2 years ago, and is easily 20 feet tall now.
