We have a wall of Ikea Magiker bookcases (unfortunately no longer made) and matching TV unit in our main basement room that houses our TV /dvd/extensive book collection. On the other side of the room, 3 more bookcases hold a huge amount of toys and games for all ages. The bookcases have solid as well as glass doors which I love because they hide a lot of things without being all closed in.

Beside it we have a wonderful kitchenette (Ikea kitchen cabs) and full bath which my husband has taken over for his morning prep area. It's perfect because he usually runs on the treadmill in the adjacent exercise room in the morning first.

We LOVE our finished basement!

We were going to put a media room in our basement but then decided against it as we would probably never use it...it's just so darn convenient to hang out by the kitchen. So we used our lower level for my craft room, an exercise room, a guest room and a full bath plus a store room. All of these things are things we could live without if we had to so we could live on one level should lifestyle require it.

However, if we had kids, making a kid space would probably be the best thing to do with the space as, as kids grow, they want their own space away from everyone and everything and basements are perfect for that. (Yet parents like their kids home so they know where they are and what they're up to.) So I'd suggest building a large space that is flexible for multiple purposes as the needs and wants of the kids will change as they grow....