One thing skyrim does really well: the continual quest accumulation.
Every city you visit, you'll get like 5 new quests, which will take you to other parts of the map, where you will find 5 more quests, which lead you to more quests, etc etc.

The end result: it never really feels like you're DONE with an area. A lot of other open world games seem to encourage you to stay in one place and suck it dry of every activity before moving on