If dinner is the most common use time, then consider that most use will be after 4pm and plan for windows that capture the late afternoon light, rather than the morning light. Pick an indoor paint color that will hide marks well, and is a regular color, not a custom blend. Buy a couple of extra gallons for touch up. Kids rooms in the basement don't work too well for kids under 4 and require an adult supervisor. You are going to want twice as many bulletin boards as you think.
Corners make nice places for intimate groupings of furniture.
If you have a fireplace, put it in a corner. Electrical outlets in the floor, which can be covered by a bit of tile, come in handy. Especially in the middle of a large open area, or by the food service. Put the dining area lights on separate circuits and include dimmers. It can be handy to be able to turn off about half the lights in the dining area sometimes.