I have two big Expedit bookshelves in my office (that our landlord nicely left for us). I love this system as it can be used as a room divider or bookshelf. Additionally there are a number of baskets and boxes made to fit the cubes that you can hide things away in. You can also purchase drawers and cupboard doors to add to it.
The one thing I have not been able to do with it yet is figure out a good way to use it for hanging files. I can fit filing boxes into the cubes, but they don't look very nice, and it's a hassle to have to pull them all the way out and open the lids to access files.
Then, when I was at Ikea on Saturday (before my nasty cold fortified itself and made a second attack) I found they have a new box designed to fit into the Expedit.
This is it. Bonus: It's only 6.99 (compared to 16-24 dollars for all the other boxes/baskets that fit the cubes). Bonus #2: It comes in pretty colors. So, I bought 3 of the turquoise colored ones.
I discussed the need for a better hanging file set up (and my unwillingness to pay $300-600 for ugly filing cabinets), and D. suggested just putting a file frame into the box! Brilliant husband I have.
So, off to staples and I bough three of these:
Actually, as it turns out I bought 6 of them, because I didn't realize there were 2 per box. Each box of 2 was about $12.00 - not bad :). Then, I set up the file frames - using the smallest length (14 inches) and put them into the boxes:
Perfect! They slide easily in and out of the bookshelf and hold about as much as a large filing box. My only concern is longevity - the boxes are cloth on a cardboard frame (the type that pop up and zip together), so they may give out after a period of use. I'll let you know though. But hey, the whole thing cost me about 40.00 for the boxes and file systems, so I won't complain! I kept them all on the bottom of the bookshelf, as I think they would be a bit awkward on a higher shelf. This would be perfect if you were using the Expedit as a room divider, as the boxes look nice from both sides and have handles on both sides.
And I think this looks MUCH better than a stinky metal filing cabinet!
This is a slightly modified version of Kath's pumkin oatmeal. It is seriously, astonishingly good!! Mine included the following:
Actually, as it turns out I bought 6 of them, because I didn't realize there were 2 per box. Each box of 2 was about $12.00 - not bad :). Then, I set up the file frames - using the smallest length (14 inches) and put them into the boxes: 
Perfect! They slide easily in and out of the bookshelf and hold about as much as a large filing box. My only concern is longevity - the boxes are cloth on a cardboard frame (the type that pop up and zip together), so they may give out after a period of use. I'll let you know though. But hey, the whole thing cost me about 40.00 for the boxes and file systems, so I won't complain! I kept them all on the bottom of the bookshelf, as I think they would be a bit awkward on a higher shelf. This would be perfect if you were using the Expedit as a room divider, as the boxes look nice from both sides and have handles on both sides. 
And I think this looks MUCH better than a stinky metal filing cabinet!
