One thing I'd like to see in Civ 4 is a "post-it" note kind of thing, whereby you can put a beacon or something at any point on the map to remind you to go back before the end of the turn and do something important- be it unfortify a unit and move it to your border, mess with a city's production, or whatever. And when you hit enter you'd be reminded of these areas. Too many times I've seen something I need to do, got to the end of the turn and hit enter without thinking and "had" to reload right away...