With those settings and content you mentioned, the 60 hours are not surprising to me. My longest render ever was about 24 or 25 hours, if I remember correctly, my average render is 2 or 3 hours. If you look at my gallery, you'll see that most of my images are fairly complex. I also use a lot of radiosity. For example, my latest image was rendered in radiosity, it has several ecosystems, billions of polygons, reflections and transparency, procedural terrains, and it rendered in 3 hours. And I think it looks very realistic, but you can judge by yourself.

First of all, I would say that you shouldn't use the pre-configured list of render settings. Those presets are very poorly balanced, in terms of AA and advanced effects, for example. You are wasting render time for no visible increase in image quality, most of the times. IMO, you should use user-settings. Peggy Walters has an excellent tutorial with very good practical advices for this (I don't have the link at hand, maybe someone else reading this thread will).

The "secret" to my 3 hours rendering time is render and atmosphere settings adjusted to the minimum setting that provide good quality. I don't put any slider even a bit to the right if it's not needed. To know if something is needed or not you should experiment. This experimentation is made very easy with that excellent document from Peggy.

One simple trick that some people neglect is the quality boost in the light tab of the atmospheric settings. In most cases, you can put that in highly negative values (like -1 or -2) without any noticeable impact in quality. The impact in render times is tremendous. Another thing is "advanced effects quality". In most cases you can use 40% or less with no visible impact in quality. Etc, etc. It's all in that precious document. :-)