I've got about 14 wooden boxes, about 30cm deep and the width of a CD, that rest on 32cm deep shelves. There is a label on the end of each box with composer/composers, or the type of music (rock, R'n B, Motown, miscellaneous, etc.) This way I can find what I'm looking for pretty quickly without going blind while holding my head sideways. I can also pull each box right out and put it on the floor to look for a CD. Automatically, what I listen to most stays at the front of each box. This is for a total of about 300 CDs.
It wasn't really planned originally, but basically gradually "happened" as I used space that used to hold LPs (i.e. 30cm deep).