Giorgio, I actually don't use CD/DVDs for any backing up of my images at all, I just use redundant harddrives as I've never been able to keep track of the CD/DVDs.
Jeremy,
Thanks for the reply, redundant hard drives here too and a stand alone back up drive. I just feel better knowing I have originals on DVD as well.
The pack rat in me likes puting them in boxes and storing them in a cool dry place.
I have been using Taiyo-Yuden DVD-R with no failures (so far). But DVD is not the only archive... We use RAID1 on the Mac, and RAID5 on the Linux server. All of this is backed up to portable firewire drives for rotating, off-site, encrypted backup. Call me paranoid!