I agree with Mac The Knife on the topic of backing up complete OS drives. You're at risk of backing up the bad along with the good - including the problem that leads to your need to use the backup. A bit like replacing a flat tyre with another tyre that has a slow leak.
What I try and do is keep strict separation between OS and data. If you keep all data under a known location, such as "My Documents" in Windows, it's easy to back up. The easier it is to back up, the more frequently you'll do it, and the more reliable it will be.
My "daily" backup is using the aforementioned SyncToy to synchronize "My Documents", Desktop & Favourites between two PCs (laptop & desktop). That way I can work on either PC, and everything gets fully backed up, as long as I don't modify the same file on both machines at the same time.
