I am attempting to setup a web/mail server and my machine is running RedHat 9 with 2-80 Gb hard drives. I also want to setup a backup system, considering I have so much drive space.

Considering those specs what would be a good partitioning strategy, and what would be the reasoning behind it? What types of backups are the most effective and how would the backup strategy affect the partitioning?

Well you have two options here:

Software raid -- I have been setting up a lot of software raid boxes lately because people want mirror drives but do not want to pay for scsi. The drive access -- read / write times do not seem to be affected and it will offer you mirrored data.

You could also setup the system on the first drive, then do a sfdisk -d /dev/maindrive > binfile ; sfdisk /dev/backup < binfile -- this will make the second drive have the same partition scheme exactly -- then nightly you could do a cp -Rdp from partition to partition keep a exact backup, or use cpio to make backup images nightly and savethem on the second drive, mount, create backup on second drive andthen umount.