Re: geographically speaking
The Colts should be in the AFC North (geographically speaking) with the Bengals, Browns, and Steelers. Indiana is right there with Ohio and those areas are natural rivals in other sports.
Actually that is how it was intially going to be. The Ravens were going to be in the AFC South. However the Rooney's cried and wanted Modell in their division so they sent the Colts to the South and allowed Modell and the Ravens to stay in the North.
The Ravens would have made more sense for the South. They are a relocation team like the Titans and had a real strong rivalry with them. Most Texans won't think of Baltimore as being in the South, however Maryland, especially Baltimore folks consider themselves Southern and they are south of the Mason/Dixon line which by definition makes them a Southern city.
As an old Oilers fan I would have loved the Texans to be in the same division as the old AFC Central teams however that wasn't going to happen.