As much as I'm looking forward to this game, I hope I don't have the same experience with it as I did with Fallout NV. I've logged about a hundred hours in that game and I reckon I'm just about halfway through it. Can't stop myself from doing every minute sidequest, upgrading each weapon and talking to every NPC in the game.
I'd feel like I'm doing a game of Skyrim's quality an injustice if I don't get 100% completion, but it just takes so much time. Hopefully there's about the same amount of content as Fallout 3, and it takes around the same amount of time to complete it (80 hours for me) so that it doesn't become monotonous