In order to address user-specific variables on a more general basis, Colorado.gov and other sites are:
A maximum of 747 pixels wide for the information web sites, and 780 pixels wide for the web applications. This insures the sites do not produce left-to-right scrolling for those users viewing the web at the 800 x 600 screen resolution.
The 'header' of the information web site is no larger than 161 pixels in height, including the logo, the search bar and the banner art on the home page.
The left navigation area for the information web site is 188 pixels wide.
Both web sites and web-based applications are center-justified.
Download the templates to see the dimensions in a visual display. The templates are in the .zip file format.