Brad, our basement is partially finished but and when my kids were younger, they played down there all of the time. However we're having it totally redone as an apartment in case my mother-in-law has to come live with us sometime down the road. In the meantime I've slipped in a nice Plasma TV as part of the deal with my wife.
In the meantime, there will be a separate bedroom, living room and a nice kitchen down there for those nights I want to be alone.