3 x Laptops 1 x media centre (Mac mini) 1 x family machine (Mac mini) attached to 2 x 1Tb software-raid drives.
Everyone backs up to the Mac Mini, and this is backed up to the 2 drives. This machine also backs up to Backblaze.
I too had an experience where I thought I'd lost all my photos of my kids (5 years worth) when a HD died. Luckily I had an earlier backup and I lost around 3 months worth in the end
When I've looked into this in the past, every provider has had issues with the new and archived content volume, and sometimes even the use of external rather than internal drives (!) that has made it unviable. I couldn't see from Mozy's site whether this was the case with them as well? If not and I can genuinely back up several hundred GBs of data (phone calls from ISP notwithstanding) and potentially add tens to low hundreds of GBs new data per month, from whatever drive source I choose, this sounds like what I want. Would this be the case from your experience?
If you're adding 50GB/month, that's at least 1GB of upload per night. You'll definitely have to have a good internet connection. I haven't had any network speed issues with Mozy personally.
I should stress too - 50GB / month is a worst case scenario, not a typical usage! Raws and processed JPEGs for a couple of big events can hit that together but I don't often have a couple of big events in the same month.
i chose crashplan over mozy, after reading some bad mozy reviews (http://wonko.com/post/it_turns_out_mozy_isnt_so_hot_after_al... for instance) . I have the family plan and uploaded 200gb so far, their upload speeds are pretty good.
The only feature I'm still waiting for, is so you can specify different backup sets to archive to your local HD and to their online sevice, but that feature should be realeased with their next update. Other than that I love crashplan, especially the eature that you cannot disable it for longer than 24 hours.
You can also seed your initial backup, that way you don't have long upload times.