dh and I recently came to the same conclusion....its all about declutter and organize and maximize the space, so we can stay put for a while. I really like the Ikea Billy boocases (the shallow, 11" ones) with doors. Some doors have the magnetic child locks and some are open. Each toy has a bin and the kids can get the bin out, play and then put away. my big kids have access to the keys, but if the mess gets out of hand, the keys go away for a while, so then they have to ask permission all the time.
but, from your post, it sounds like you do already have storage? if so, you could rotate in and out the toys. for example, I have a bookcase in our family room and the bottom shelves are for DD2, she has 5 or 6 baskets or toys down there at a time. its a good mix for her. enough that she can pick out something to play with, but small enough that she can usually clean up with some help. I rotate the other toys into boxes in the basement. I have found that if she has all the toys out, she doesnt' really play, she just dumps toys and throws them. like she gets overwhelmed. I pull out a puzzle every few days (or 2-3, depending on age), and for the older kids, i pull out a game or two each day. it helps to have things rotated.
we love hooks on the wall for dress up clothes, next to a low mirror on the wall. these usually stay in the kids rooms, but i have considered adding another in the basement play room. there, dress up cloths stay in a box. for sure put the play food with the kitchen. like things together! and honestly, feel free to pack away toys that are no longer favorites or that she has likely outgrown. Books go in a cabinet with a door, but a couple dozen stay out on Ikea picture frame ledges. kids have these in their rooms and down stairs. I pull out seasonally themed books and they keep out the favorites of the week.
but that said, I don't really feel like I have a good handle on our stuff. thus the purging. so i'm looking forward to other suggestions!
loving my dh and our littles (dd ~ 11 yrs, ds ~ 9 yrs, ds ~ 7 yrs, dd ~ 5 yrs and baby brother ~ 20 mo)