Ok that helps. I used to do tech work but got out of the game 5 or 6 years ago. So here is my official and now quite non-professional opinion.
For what you're doing, I wouldn't even bother with full system backups nor on-site backups. Buy an off-site solution, Carbonite, Mosy, etc, target any and every doc folder of any sort and f'get-a-bout-it and here's why. Doing on-site full sys backs will indeed allow you to back to last week within a few hours in almost any scenario (i.e. pretty much all but the aforementioned destroyed building scenario).
But here are the downsides to that. First off, it takes your machine back to last week. Which is to say it was running last week. But it was probably running on an OS install that was more than a year old and therefore not exactly fresh and therefore not exactly perfect. IOW it gets you up and running back to last week worts and all with any and all bad registry entries, corrupt system files and half broken flaky software you had on your system at that time. That's number one. Number two is that it does that only if it actually works. Because my experience has been that ALL unattended on-site full system backup solutions are fraught with peril and ALL will stop working eventually without notifying you even if you have all the boxes configured correctly to do verification every time and notify you via 4 different methods should any verification fail. Ok I'm exaggerating a little there, but only a little. They all fail. All of them.
OTOH my experience has been that cloud based data file only solutions almost never fail. They are literally set it and forget it solutions. And the recovery scenario there takes a bit longer but achieves a much more desirable result for your trouble. Basically if your machine has a nasty infection or your hard drive gives up the ghost, you replace hardware as required and then you do a complete restore from the original hidden partition or recovery DVD. Then you install all OS updates. Then you install all required software either from the original discs or (as more and more software becomes subscription based) from the web. Then you reconnect your cloud backup account, do a full restore of your data and boom, you've now got a completely fresh completely clean install, i.e. faster machine than you probably had last week, so you're up and running like it never happened only better.
And of course if its a scenario where the building is destroyed, your plan is collect insurance check, go shopping for new machine and new copies of disc based software (you are insured for that right?) download your subscription based software, reconnect your cloud backup account and Bob's your uncle.
It really is a much more elegant solution all around. If you're skeptical, do on-site full sys backs once a month, with data backs once a week to an external drive and also do data to a cloud backup account. But I can just about guarantee if you do this, you will find that you only ever do recoveries from the cloud account and never once use the on-site stuff.