I used 1/8" plywood to make an "egg crate" that slipped into the
drawer. Each square of the egg crate was the width-of-a-cd X about 4".
Each square is loosely filled. This allowed me to space out the CDs so
I could flip through them and see the fronts. (As opposed to tighty
packed where you can just read the spine. So this is is a good idea if
you expect to have some excess drawer capacity. Of course you may
eventually fill it to tightly packed. (I have a store near me that
buys used CDs. It's better than holding on to CDs that I would never
listen to.)

Mitch