I use it for images of the OS and boot partitions.
Since it compresses better than the other ones I tried,
I have one CD for every machine and one DVD with the data for all machines in the safe.

I stay away from DVD-spanning operations for large amounts of data,
since it is easy to loose a disk or get mixed up:
if your data is large/important/worth money, get a tape drive.
But that is a personal handling problem <g>, not a technical one.

For purely personal needs it is more than enough:
best is to create a special partition for your data
and then you have a safe and cheap way for backup.

HTH

thomas