I agree, having to re-do your downloads is a great opportunity to start fresh (and organized). I regret that I wasn't organized from download one.

I'm obsessive with my backups. I keep a cd backup of each hood AND (since the pops put a second hard drive in my machine) I have the whole sims 2 thing (yes, that huge thing) backed up there. (oh and I save my dl folder to disk, too)