Mepis is great for a newbie, but it's not actually "true" Debian.
If you have a particular reason for desiring "true" Debian rather than Mepis, the version of Debian you probably want is Debian Sarge. Debian Sarge is currently the Debian Testing branch, so either download the first Debian Testing CD or the minimal install FTP CD.
When it asks you where you want to install software from, select either http or ftp, so most of the actual software gets installed directly from the 'net. Naturally, you only want to do this if you have a fast internet connection.
If you don't have a fast internet connection...Mepis is probably a better idea. A much better idea.