For a typical installation around 4or 5 CDs would really do. But 14 CD set contains around 16,000 packages. (If you just want a minimal installation you can use the net install CD and then use your Net connection to install over the Net.)
Etch or Sarge, Debian packages are included in the 14 CD set according to the popularity. So if your favourite package is not very popular, most probably you wouldn't find it in the first 2 CDs.
I'm a user who can justify myself for having all 14 CDs.