It is critically important that people understand that user data file backup (which is what has mostly been what has been mentioned on this topic) and full system image backups (which include the operating system and the user data for all users on that machine) are two completely different things.
It's actually a good idea to take both, but if you have to choose one it's the full system image backup, as it will snag everything you need to get yourself back up and running should you have something like a main drive failure, while a user data only backup will not.
Brian - Windows 10 Pro, 64-Bit, Version 2004, Build 19041
It’s hard waking up and realizing it’s not always black and white.
~ Kelley Boorn