The Elder Scrolls V: Skyrim
Alright, now - at 135 hours - I think I'm really done. I restored the Thieves' Guild to its former glory, I joined the Dark Brotherhood (and also restored them to glory), championed the crazy causes of all the Daedric princes, broke level 50, and now I have a full suit of jester armor. (Not what I normally wear.)
I'm not sure if I made this point effectively in my last post, but Skyrim is not a perfect game. Setting aside its technological issues (and the aforementioned unplayability of melee combat), I'm also disappointed by the damage-to-magicka ratio of the higher-level Destruction spells, annoyed by the vast meandering Dwemer ruin dungeons, and irritated by the frequent appearance of a random dragon just when I was in the middle of something. The genius of Skyrim is that it's so vast and robust, that its shortcomings have no problem being overshadowed by the other content you can take part in.
I wouldn't be surprised if, a few months from now, I find myself back in my save file -- running more errands for the towns in which I'm not yet eminently trusted. Then what's to stop me from going on a killing spree, assassinating all those gullible idiots? And that's when things will really get interesting.
Progress: Level 50 winner of everything