An interview with Laurie Orlov, a research director at Forrester Research (Cambridge, Mass.) goes over the three models for a CIO.

• The first one is the solid utility. The IT organization must provide cost-effective, dial-tone reliability. That is, the network is always there, the PCs function, the help desk responds and the back-office applications are up and working. The CIO typically reports to the CFO, and costs are expected to be transparent and reduced over time.
• The second is the trusted supplier, in which you add project delivery to the solid-utility model. Some firms need centrally managed application projects to support process changes in and between functional departments. In these IT organizations, the CIO is likely to report to either the CEO or the COO and the enterprise expects to have all the infrastructure capabilities of the first level, in addition to having application projects managed centrally, and delivered on time and within budget.
• The third archetype is the partner player, where the business is IT and IT is the business. IT organizations in these firms pour their energy into creating unique and competitive solutions for customers, suppliers and internal business users. As a result, there is little time for the delay in requirements translation between business groups and IT.

Source: Bank Systems & Technology : CIO’s Need to Understand Their Roles to be Successful