When that author should choose a CC license for the first time Creative Commons have made it easy to choose between the different licenses. Using the license selector (link is external) also makes it easy for those who are completely inexperienced users of Creative Commons licenses to determine the correct license.
What many are wondering is how many limitations you should choose to associate with his work. There is an axis between more open licenses with few limitations and the most restrictive ones that have limitation on derivatives and commercial use.
License CC-BY and CC-BY-SA (includes CC0) is often defined in a separate category licenses that support the «free culture.» My advice is that you should use these licenses as often as you can. The statistics that summarises the use of CC licenses globally also shows a clear trend that these «free culture» licenses are the most popular. This is good news because it provides even greater freedom for those who want to reuse, even for those who engaged in commercial activities.
The most popular license is CC Attribution-Share Alike (BY-SA). 37% of all work published are released under this license. By comparison, only 14% have chosen to use CC Attribution-Noncommercial-No processing (CC BY-NC-ND). One of the most restrictive licenses.