This picture is just to the left of the first picture, and it shows some colorful cottonwoods? in the distance. Most of the cottonwoods around here have shown good color for several weeks but there are some cottonwoods/poplars that are big and wide but more upright than multi-trunked/spreading that are still mostly green.

Still, cottonwoods are by far the most valuable tree for fall color when driving around the countryside (or the deserts of western Colorado/Utah etc) and in towns they are one of the top trees along with green and white ashes. I would place maples (colorful but not so many of them and not so big, and honeylocust in a distant second class. Everything else is only a minor contributor I think when you are driving around. Up close you can appreciate the nice fall color from some bush or a shorter tree or a less common tree.

Its tough to pinpoint what you're referring to in the pics.

There is a subspecies commonly called Western Cottonwood. It should be easy to distinguish the two you are referring to. Aspen has the white"ish" bark.

Eastern cottonwood is a crappy weed tree around here with no fall color.
There isn't a single tree growing in WI that I hate more. Occasionally you come across very old specimens with quite a bit of character, almost reminiscent of Burr Oak, but its rare. Usually they are riddled with canker or damaged branches.

Several came crashing down in my neighbors yard this past winter with the heavy wet snow we got...dumb things were leafless and still fell apart.

Here is a link that might be useful: Eastern Cottonwood

Yes your Eastern Cottonwood looks just like the Plains Cottonwood except we get good color from ours. See http://www.coloradotrees.org/feature_trees/cottonwood_plains.php
I agree that they aren't good trees for cities and yards, we had an major October snowstorm a couple years ago and cottonwoods caused lots of damage. I want to keep the narrowleaf cottonwood in our yard under control and cut it down before it gets too big. My plains cottonwood has already gotten too big to handle myself but maybe I should remove it too.
Still the cottonwoods provide a good bit of the tree cover and fall color in cities and towns here, and are extremely common along creeks and in fields, and if the ash trees eventually die we will notice the cottonwoods even more unfortunately.

Here is a link that might be useful: http://www.coloradotrees.org/feature_trees/cottonwood_plains.php

Closely related but definitely a different tree.

Eastern Cottonwoods are common here, too. Typically they get some sort of fungal or insect blight and lose many of their leaves before fall even arrives.

We have scattered cottonwoods down here. They have a fairly good yellow show in the fall usually right before Thanksgiving.

Here's a recent picture of some Cottonwoods (and other trees/bushes) here in Nevada.

Today, Nov 21, we got a big freeze and snow which might finally end the cottonwood color season which started in late August. We had a long fall color season for all trees this year, and yesterday there were still a few big cottonwoods (or some kind of Populus) with yellow leaves. The maples turned out to be better than I expected, maybe because the season was so long that the dark purple/magenta colors of some trees mellowed to more pleasing (for me) red/oranges.

I would rate the "fall color value" around my town in the greater Denver area this year as follows (relative scale)
10 Cottonwoods
7 Ashes
4 Maples
2 Pears
2 Aspens
2 Honeylocusts
1 everything else: crabapples/apples, oaks, lindens, willows, hackberry, catalpa etc

I'm taking into consideration the size of trees, abundance, duration of color, everything.

Here are some reports I found about street trees and park trees in Boulder and Ft. Collins, two cities in my general area:
http://www.fs.fed.us/psw/programs/uesd/uep/products/psw_cufr624_Boulder_MBCA_web.pdf
http://www.treebenefits.terrasummit.com/Documents/General/Fort%20Collins%20street%20tree%20analysis.pdf

I think I already listed the main trees in the area, but the reports also mention American Elm, Siberian Elm, plums, Kentucky Coffeetree and Russian Olive--none of these seemed to be a major contributor to fall color in my area, at least this year.