I’m looking for an open source or inexpensive option for a simple map of the united states to plot geo points on OR fill in states with colors like Google Analytics does for traffic.
I don’t want anything fancy, just a map with states and the ability to darken areas, states or plot dots on it for a location service I’m building.
Google Maps can plot the markers, but I want this to be stupid simple and a little less feature rich. Other popular mapping softwares out there are also too feature rich (Open Maps, MapQuest, etc.).

I guess you’re looking for something like this:
http://www.ravelrumba.com/code/demos/us-map-raphael/demo-animated.html
This is a Javascript map of the US, with roll-over states. It uses the Raphael library. The Github code also includes links to the SVG map that he used as the source data, and a link to a tool for converting SVG to JS data suitable for Raphael to use.
The Raphael library itself has a similar demo on their own site for Australia.
I hope that helps.