More BookCase In The Study Room

I need more bookcases for my study room. Although I already have 2 book case, but it just don't enough to store my books and business documents. Since the study room still able to place 1 or 2 book case, so I think I better get a large book case from Studio RTA Furniture website. That furniture looks very nice and easy to assemble too. hmm..But should I get a bookcase or file cabinets? haha..Seem like I need each of them. :p