Listen to co-workers
Your colleagues will be a great source of ideas. Other than citizens themselves, they are in the best position to know what is most frequently asked of their department. Establish a process to gather ideas from the various departments in your government. No matter what method you choose, it's important to get others' ideas on what features, services, and content should be included in the site.
For example, one county used quarterly cabinet meetings with department heads to encourage contributions and ideas. Other representatives said they gathered input through more informal, free-flowing discussions with key people.
The Montgomery County Web site provides demographic and census information that can be used by citizens and businesses for research.