Two threads of this going right now. Here's what I posted in the other one:
I use a combination of mineral display boxes and vintage wooden wine and cigar boxes for folders. The boxes are pretty easy to come across if you fish the right places---liquor stores, smoke shops, flea markets, whatever. I finish them however I want to, line them with some cheap black Elvis velvet and lay in the knives.
Mineral display cases usually have glass insert tops and can be very nice. You can pull them up easily on Google. Lots of varieties. You'll want something flat with mainly square inches of floor space. The ones between roughly 8x10" to 10x14" or so are the handiest.
I keep the boxes in a vault and have a box out at a time, each holding a week or more's rotation of varying types of folders. I also have some of those desicant packs out of products when I see them and each knife tray has one in it.
I think another good way to go are some of the simple tackle boxes and Plano type boxes with compartments. Seems like a great inexpensive way to store them too. On the higher side, I like seeing the multi-leveled, multi-drawered wooden craftsmen's chests and the rolling tool chests full of nice knives. Some of those are really cool.
I store most of my fixed blades in Storm, Otterbox or Pelican cases unsheathed. All the sheaths are in one place.