I'd say a single play through, with the main quest, side quests, and all points of interest on the map, might take about 80 - 100 hours.

So there's three different life paths, that will ultimately affect the way your story and game turns out, and your choices determine what ending you will get.

And then, changing your gender changes A LOT in the game, as well.

So I'm thinking I'll get anywhere from 300 - 500 hours out of it easily. Cause I plan on doing multiple play throughs.