Being in a CEO position, I would think to align the CIO with other chief officers like CFO and COO, directly under myself. They would be the head and most responsible for the IT initiatives throughout a company. Of course their focus is quite a bit different than other officers in upper management but the CIO is just as important. The rest of the organization structure would be aligned down from there.
The CIO should report directly to the CEO not the COO. They are the leader and focal point for IT guidance in the organization. A person of this position should have regular contact and exposure to the CEO. If there were some important changes that needed to be made the CIO should be able to let the CEO directly. Information that will come from them would be things that should not be left up to the possibility of falling through the cracks. Not saying that if the CIO reported to the COO, then then pertinent information would not eventually get to the CEO. I just don’t believe it is something that could be afforded or left to chance of delay. There are many facets of a company that are IT driven and related and the CIO requires and understanding of both the IT perspectives and the local business culture. With things constantly changing on a daily basis they need to be in contact to those leaders. The CEO would be able to articulate the goals of the business and the CIO could let them know in real time what it would entail to make that happen.