The stacking acrylic trays hold paper sets that I want to keep together by manufacturer, and pages in progress. I usually put my most recent paper acquisitions in there, too.
The colored drawer thingy on the far left sits between two windows and holds my stamps and ink pads.
I have some big, square open shelves built in to the cabinetry unit. Right now they are holding my tackle boxes of small embellies organized by color, and a bunch of completed layouts waiting to be put in albums.