I’ve found a combination of software that lets me do most of what I used to do with Retrospect. In some ways, it’s more convenient; in others, it’s less. It does, however, it give me more peace of mind.
My twice-daily incremental backup is now done with Synchronize! Pro X. This copies everything to an external FireWire drive, and it uses Synchronize’s archive feature to preserve old versions of the files. I compress the archive folders to save space. This is not as nice as with Retrospect, because Finder-format backups are inefficient, and the archive folders are a poor substitute for Retrospect’s snapshot feature.
To archive old versions of files and allow for off-site backups, I use CDFinder, DropDMG and Toast. I have a DropDMG configuration that creates encrypted, compressed disk images that are segmented into DVD-sized chunks, tagged with the date, and saved on the external FireWire drive. When I’m done for the day, I drag my key folders onto DropDMG, and by morning I have a bunch of .dmg and .dmgpart files.
Every few days, I burn a set of the disk images to DVD. First, I mount the disk images and drag them onto CDFinder to catalog them. Then I burn them with Toast. Overall, this works better than it did with Retrospect. By snapshotting everything to disk images before burning, I can do work (using the files that were copied to the disk images) during the burning. With Retrospect, I always dreaded starting a new DVD backup set, because it meant hours of swapping disks, and I couldn’t, for instance, run Mailsmith while backing up the Mail folder. Also, Toast is much faster at burning than Retrospect, and it fits more per DVD. A possible downside is that the DVD backups are no longer incremental, but I’ve decided that this is a plus. With each DVD set being a full backup, I can take it off-site right away.
For restores, it’s a pain to copy multiple (usually one or two) .dmgpart files back to the hard disk before I can mount the image. Restoring is rare, however, and this procedure is much faster than rebuilding a Retrospect catalog. It also works with a fresh OS installation; there's no need to locate a Retrospect install CD and download the update that lets it launch on Tiger.
Update: As of August 2005 I am now using DropDMG instead of Toast to do the burning.