problem with it though is that the quests are rarely fleshed out with meaningful information as it was before they started putting markers all over the place. In morrowind all the info would be in the quests giver's dialog, or you'd have to find it from relevant npcs - or risk wandering the wilds for hours without end. I tried getting rid of markers in oblivion and ended up always having to turn it back on from lack of information. I.E: Some cave I was told to go to didn't even come with a direction because the game would assume you would follow your marker.
If the quests are adequately written and designed, I would love to turn the markers off. And speak to most npcs to try finding if any have a quest ect... I find it much more fun to play, same as since its an mmo, sometimes I might turn it on (when questing in a party, otherwise I'll most likely lag behind and you know...). However don't put the effort into the feature if the quests are designed to work WITH the markers.
anyway...