Steve Swift writes:

In calculating the space needed, it's worthwhile allocating ~200Mb per
CD for the MP3 files, and also about 700Mb to keep an image copy of
the CD itself.

This is probably more complex than Derrick needs. Since he just wants
to be able to play all the CDs he's got, it would be more
straightforward to just store everything in a lossless compressed
format like FLAC, and not worry about MP3 copies. With that you're
looking at about 400MB per (full) CD.

Big hard disks are cheap these days -- 400GB for under sixty quid. My
preferred approach would be to buy four (or more) large SATA disks and
use them as a software RAID5 array. The performance will be more than
adequate for the application, and using RAID5 means that you can
replace a failed disk without losing any data.

--
Adam Sampson http://offog.org/