Even with the ASB nature of this, I am assuming we are talking about a situation where the lakes somehow survived until modern day? If so, this map gives us an idea of what the Great Basin Lakes chain would look like:
http://en.wikipedia.org/wiki/File:Lake_bonneville_map.svg
There would a neat Indian civilization in the area that eventually loses out to European settlers.
There might be greater Spanish settlement in the southern portions, but I think the northern areas would be limited to a few more Spanish missions. Eventually, the area is lost to the United States (I know, butterflies, but unless we start with certain assumptions, it's impossible to hypothesize).
So we're basically talking about how the US would be different if there were several large lakes in the American West slowly evaporating. To start, the population in Nevada and Utah are much higher with greater agricultural output. With the mineral resources there, there is also likely a large manufacturing economy perhaps more similar to Minnesota than any other state. Starting in the 20th Century, concern over the ongoing depletion of the lakes will result in major government engineering and water rights disputes to retain the lakes. Long term prognosis for the region is bad with the population beginning to decline as people move to other regions.
Challenges facing the US is similar to those facing the Aral Sea region and Lake Chad. By late 20th century, there is large ongoing desertification research based in the universities of the area to study how to use least water as possible and retain natural water. The area is a world leader in countermeasures and technologies devoted to solving the problem which may mean various spin offs that help other areas of the globe.
With the water necessary to support a large population and diverse economy, Las Vegas never happens. Atlantic City remains the gambling mecca of the United States. Because the area would be a prime immigration spot, the Mormons might never settle Utah in large numbers. Instead their numbers are more dispersed, and it is even possible the area with the largest Mormon population is in northern Mexico making Sonora the de facto home of the Mormon religion which has all sorts of implications in Mexican history.