I'm nearly halfway through my quarterly backups, and it's getting to be pretty hard work as I successively hit the DVD storage limit and start shuffling things around (I'm doing overlapping backups, but even then there are some things I'd rather have in a single disc).
For the curious, my backup scheme revolves around throwing copies into a 250GB external Firewire disk (therefore creating an updated replica of pretty much everything) and then building DVD images from that. This works for everything but my MP3 archive, which is on a NSLU2 (occasionally replicated to another box, but which I can restore the hard way by ripping everything again), and Virtual PC images (which get replicated to the NSLU2 from whichever machine I'm running them on).
Work e-mail, after triage (which happens on the day I receive it) pruning (I don't store every message - far from it) and duplicate removal (based on the Message-ID header) is now 4.9GB - nearly 1.1GB this year alone, including Friday):
[rcarmo Work]$ du -k -a 2005 551264 ./2005/Q1 557384 ./2005/Q2 33496 ./2005/Q3 1142144 ./2005
Personal e-mail is a small fraction of that (except mailing-lists, which I don't keep), as are my development and site file trees. My photo archive was somewhat trimmed (removing unfocused and blurry pictures) to fit into a single DVD, and I'm now cleaning out my home directory (site artwork, documentation, project stuff, etc.).