YAY! Debian!

Excellent. You won't need to download all the CD images unless you want more software.

Once you have the CD image, you can pick from the following flavors:

Gnome - good for modern computers, you will need to download the first two CD images.

KDE - good for people who want a traditional menu interface. You will need to download the first two CD images.

XFCE - good for low resource computers. You only need the first one CD image.