What do I do with this space?

So here is my dilemma.  In our new house there are these shelf-closet-like spaces in both the upstairs bedrooms.  In the kid’s room I’ve made one of them into a bookshelf and the other one will be shelves and a desk area.  In our master bedroom, I’m not quite sure what to do.  There is a space underneath, so someone suggested putting in a nice chair and making a bedroom vanity of sorts, and making it a spot to put on make-up, etc (maybe a mirror up on that wall).  Or, I could put up some floating shelves (IKEA shopping trip coming up!) and use the spot underneath for…ur…storage?  I’m just not sure what to do.  Any suggestions for this odd space in our bedroom?