Hi B.,
Not to be contrary, but I tend to avoid restaurants with play rooms. We have had nothing but bad experiences with restaurants which allow kids to leave the tables and 'go play' away from the parents, mainly because there will often be a few kids who, away from parents and out of earshot, will misbehave with the other kids. Think toys being grabbed out of each others' hands, the kid who wants 'all' of one item, and playground justice in working out problems. This is the reason why so many moms of young children make playdate arrangements at the park-- there are no toys to fight over. So, I'm not trying to be a Debbie Downer, but those are some things to consider. Unattended children and poorly behaved kids who were bothering my child (at our own table, no less) finally drove us away from one of our favorite places... we loved the food and atmosphere at the beginning, but adding a play corner they lost a lot of regulars, both with and without children.
Some of my server friends, too, have had a lot of trouble with kids being underfoot and running around. If you have a big tray of plates, it's really hard to see toddlers who pop out from under tables.
What I HAVE liked and have seen work really well at restaurants are books/games/small toys which can be stored on shelves and brought back to the table. Think baskets of crayons, a roll of paper/pack of paper, coloring books, lots of kids books (simple, easy -to-wipe board books for little ones and things like :Book of Jokes, picture books, Almanacs, etc for the older ones-- thing which invite conversations at the tables). We generally pack an activity bag for our son, who is seven-- we've been doing this since he was old enough to sit alone at a restaurants. Activity books, crayons, markers, small cars/dinosaurs, small magnet sets-- all of these allow the child to be entertained while they are seated. I like this more because my child is with ME, and we are going to a restaurant to spend time together as a *family*. It allows me to teach him the normal etiquette for nicer restaurants as well. I am drawn to a place like that. (When my son was a toddler, if he needed to run, my husband or I would take him for a short walk around the block. We wanted him to learn that we NEVER RUN in a restaurant.)
Good luck on your venture... these are just a few things I've thought about over the years as a mother, and my own preferences. and no, you really don't have to have media... kids of all different ages will want to watch different things, and some little kids won't be ready for what the older ones would find boring. As I said before, restaurants should be for family time... after all, anyone can have dinner in front of the tv at home. That would also be a detractor for me, not a draw. I realize this ended up being more about my parenting philosophy than anything else, but that's my take on it.