Our house suffers from a serious lack of closet space. For years DH and I talked about getting someone to come install a ton of shelving or build closets, but we never really did anything about it. Then we found the Expedit bookshelves from IKEA, and they've been a lifesaver for us. We have 2 huge ones in the playroom, another as part of my desk, and a smaller one right next to the door that we all use as cubbies for backpacks, papers, things that need to be dealt with, etc. We're finally able to sort of stay on top of the messes and clutter now.
In the middle of redoing the playroom, when we first put everything inside the shelves:
My desk:
I don't think I have a photo of the cubbies.