Cool Beans System Info includes tons of customizable options, including program colors and network settings.

The above screenshot shows the options for the main window.  Here you can change the colors of the main window and its opacity for when alpha blending is enabled.

Each graph, e.g., CPU, has three colors.  The low end of the graph is the bottom third, which by default is green.  Medium values - the next third - show as yellow, and high values of the graph are displayed as red.  These colors can be changed to anything you'd like.

The Network tab requires some explanation:

This tab adjust the colors and upper graph limit for the network window.  If you have a cable modem, you may wish to adjust this limit to around 200 to 250.  Dial-up users may want to adjust it to 5 or so.  The network window graph displays a bar chart and time series graph.  Colors for these can easily be changed here.

Here are the options for monitoring the CPU, and it is identical to the RAM and Swap tabs:

Again, here you can customize the colors.  At the bottom left, you can change how the program deals with alpha blending.  Standard alpha blending displays the program window at a constant opacity, e.g., 60%, when alpha blending is enabled.  Variable alpha blending, on the other hand, automatically adjusts the opacity level according to the CPU usage.  In the above example, the window would be about 0% opaque (totally transparent) at CPU 0%, and 100% (not transparent at all) at 100% CPU usage.  Variable alpha blending allows you to ignore the window until critical values are reached.

The last tab is the miscellaneous tab, Misc, and it looks like this:

This tab has only two options.  By default, the tray icon is a graph.  Here you change it so that it numerically displays your CPU usage.  The other option, "load with windows," sets the program to run automatically when Windows starts.