I'd like to be able to place markers on the map. Typically, when pursuing a quest, I get sidetracked because of some new tower, cave, etc. and then my quest gets delayed. Being able to mark locations with comments such as "check out this cave", or "unexplored town", etc would be very useful and I could return to those places when I had time. Also useful to mark places where you may have had to drop some stuff due to being overloaded and then finding that spot after divesting yourself of some weight in a store. You could also use it to mark places where you can get good prices or where you can sharpen your tools. There was a mod in WOW that allowed us to do this and found it very handy.