I feel safer already.
I've got a metric crap-ton of images on my home computer. And another metric crap-ton of music files. And far fewer (tho no less important) documents and other little files. All of this is backed up semi-regularly to an external USB hard drive. Thinking that wasn't enough (what about fire? Flood? Theft?), I decided to try one of the internet-based backup solutions.
I'd heard good things about BackBlaze and, after comparing them to a number of other similar companies, decided to try them out. They offered a 15 day free trial, which (for me) is basically a joke. My 250+GB of data would take far longer than that to upload (even via my crappy cable company's crappy cable modem). After the free trial, they cost $5/month for unlimited storage. So on December 10, 2008, I started my backup.
Flash forward to today, February 9, 2009, nearly two months later and the backup finally completed. And at that, the only reason it did so so "quickly" was that I lugged my home PC in to the office and connected it to our 3Mbps (upstream) business-class cable connection, which is more than 10x faster than my home (upstream) connection.
From here on out, the home connection should be able to handle the incremental updates. I figure after an infrequent heavy-shooting weekend, I'll have a couple of gigs to upload at most (after I dump all the junk shots...something at which I'm getting much better). And that should happen relatively quickly.
Surprisingly, my crappy cable company (is that redundant?) didn't scream too loudly when I pushed ~200GB up through their wires. I did get a couple of out-of-the-ordinary robo-calls from them, which I assume was them trying to yell at me. But if you want to yell at me, call me directly and yell at me. Don't call me and leave a message asking me to call you back so you can yell at me. Eff that.