My primary backup is still Retrospect, but it's creaky and buggy with a grim future. While I'm waiting for something better I think I'm going to start using SuperDuper to mirror some of my systems. Kind of a redundant backup to my backup that I'll do every few weeks. I use USB enclosure drives for my backups (two enclosures, one offsite), with the new cheap 320GB drives it's not hard to keep a couple of images as well as the Retrospect data.
PS. I am a bit of a nut about backups. In 19 years they've saved me from catastrophic data loss at least five times.