Sid Meier's Civilization V
23 days 15 hours
The Elder Scrolls V: Skyrim
5 days 19 hours
5 days 12 hours
4 days 9 hours
Haven't managed to play it yet, as naturally no one was online pre-release. Will be putting it through its paces this weekend.
I'm quite happy to see that there's an new 'Online' game speed though, which is even quicker than 'Quick' and twice as fast as a normal game. There are also 3 multiplayer scenarios, all of which look like they can be completed in a single evening's play. Hopefully there'll be more of those to come.
Of course, all of that will be for nothing if it's as broken as the Civ V multiplayer. Stay tuned.