It took me 65 hrs to play it through the first time, and only 12 to play it again to get the outcome I wanted. I skipped many of the quests the second time through.
Now I need to play it through once more and try to get ALL of the quests I can possibly get without doing the core missions and ending the game. :)
Then later perhaps I'll play it through and take the side of the evil folks, then maybe the neutral folks, etc. When there are three major groups that can 'win' and over a dozen smaller ones that you can have various reputations with, the game is pretty huge.
I'm loving it.
Some of the bugs are a bit annoying though. Save often, and use real save points, not quicksaves. The quicksaves won't be there to save you when the game locks up. :)