Req Clarification on the Amount of Content

I have heard the figure "40 hours" mentioned many times with regard to content, and would like some clarification from Portalarium on the amount of play time I can expect.

I'm not thinking only of a main quest line, but other activities. As I mentioned on the KS comments
It sounds to me that one of the main foci will be exploration,
therefore the search for the unusual/uncommon is a good time sink.

In an ideal world, everyone would be able to have unique experiences. Whether it is to craft something unique, find something unique, or see something unique. Now we aren't talking about an ideal world here, and I don't expect the above. But I am curious how close we might get to this ideal.

I am looking for some reassurance that after pledging to get a house, I won't exhaust its possibilities anytime soon. On one level, I am donating in the hopes that the state of the art can be advanced. On another level, I am hoping to personally benefit in the form of enough entertainment to offset some of the cost.