You might think about something like Carbonite or some other online backup. I think I pay $60 per year for it. Because it runs in the background, it took a long time, maybe a week or more, to do the first initial entire backup of my drive, and it can take a day or two to fully back up a big upload of raw files. I think when I got back from a month away last April and uploaded a months worth of shooting onto my hard drive, it might have taken a couple of days or more to get all of that fully backed up. But it always keeps me backed up without any real effort on my part beyond the initial setup to make sure it was backing up all of my data but not my applications and stuff. I have a hard-drive too that backs everything up with Time Machine and when I need to quickly restore something I've accidentally deleted, that's the quickest and easiest option. I've never had to restore anything from Carbonite, but I went in a few times in the first several months to make sure all of my work was current on there and it alway had the latest and greatest. To me, there's a lot of peace of mind in redundancy. I figure either my hard drive OR Carbonite could fail me, but if BOTH do at the same time, we're probably in the midst of some sort of apocalypse or something and there might be other things to worry about!
For me, Flickr is only a backup of absolute last resort - its basically just to share stuff with family and friends and anyone else who's interested it seems. And I love printing a book every year, but that's more to look at and give my kids rather than a real backup strategy. But I suppose years after I'm gone, they may have still hung onto those and my digital files will likely go out the door with my last computer.
-Ray