I will tend to stay in the first town and around it for a good number of levels 10-12 maybe exploring a few dungeons nearby before heading off to a small town somewhere nice looking to get to 20 or so. by 25 or so I expect to have only gone to less then a third of the map and only explored maybe 10-15 dungeons.
At that point ill expand outward a fair bit and explore 40 or so dungeons and get to more of the cities and towns.
Even by level 50 O wont have explored the entire map but once I reach 50 I will do so.