Gonna have to say definitely Skyrim. While call of duty is great it doesn't quite capture the open world free roam aspect. Actually it doesn't capture it at all.
From what I got the story lines are not as connected as you'd think. It's basically that all the lands are in tamriel but they don't share allot of the same story aspects
Goin to the skyrim midnight release. Worth it i can tell you that and i haven't even played it yet.