On my internal HD, I have 2 main partitions (I have more, but they're not important in this demonstration
): one for Window, one for my documents.
I have 3 external hardrives. One (320gb) HD stays home, another one (80gb) stays with me -- they both contain the same files, but I do keep some more crap on the 320 gb : movies, audio files I don't care losing). Once every 2 weeks, I exchange the smaller 80gb portable drive with another identical one kept at my friends' place for extra security. So... TOtal : 3 external HDs, but only two that I have with me every day.
Here's approximately (I'm leaving some details) what I do :
Everyday :1- I use SyncbackSE (might replace it with the faster Super Flexible File synchronizer in a few months) for full synchronization of my personnal files (not the OS) on two external hard drives.
2- I use SyncbackSE to make incremental backups on the two external hard drives. (So, if something weird happens with a specific file, and it's corrupted on the full "sync backup", I can always go back in time and pick the good one.)
Once every two weeks or month (depending on how many modifications, configuration changes, I make) :
3- I use Acronis True Image to backup my Windows partition. (It's been VERY usefull)
I usually try to keep as many versions as possible on the 320gb HD, but only 1 or 2 on the smaller ones. I keep track of what these images contain, etc.
Voilà. All this takes a bit of time to configure, etc., but it has now become a 2nd nature, and doesn't take much more that a few minutes/day (the backup itself takes about 15min : this will vary, depending on file size, etc.). At first, I had trouble to "safely remove hardware" before unplugging my HDs, and I "lost" quite a bit of time when I was still experimenting with different backup style, naming protocol, etc.... But now, everything goes quite fast.
PS: I also have a thumb drive on which I make quick incremental backups (SyncBackSE) when I'm on the move with my laptop (so, if I drop the beast...).