That's cool and all? But I backup my email, contacts, new designs, accounting, etc once a week to a thumb drive and my 'data' drive once a week.
Worse case scenario? I reinstall xp onto a system, and copy the data back to it after re setting up the shares. 2 hours tops... Not that I discount those services? I just think one could be better served doing local backups... I mean if anything major happened, I still have my local/thumb drive/sdsc backups to copy the data back. Yes it sucks installing programs (and iso's are good), but this is a file server... it doesn't host programs... just data files... of which I have multiple copies.
Switching it all to a nas, is only going to save me electricity bills... something I should have done long ago... plus, I free up a monitor.
Fire or flood will likely destroy both your computers PLUS the locally stored backups (since this sounds like your business, a "flood" can be the building sprinklers being inadvertently activated). You need an offsite backup of some kind -- cloud, removable hard drive, tape, DVD-ROM, etc. Choose whatever suits your fancy.
I wouldn't personally consider anything stored on a thumb drive/SDSC card to be a backup; they just aren't reliable enough. For backup you should be using a RAID array of some kind so that when a drive fails you can rebuild the array from the remaining drives (a NAS is typically configured with a RAID drive setup). Something like CrashPlan may not be conducive to your computer setup, but you need some kind of off-site backup. I don't think you've actually considered a "worst case scenario" yet where everything in your house/building is destroyed...
"Two is one, one is none"