If you know your way around Windows (PC savvy or above), then Cobian is good. It's the one I use. I like it because it runs as a service and is "fire and forget".
The reason I say if you know your way around is because it's open source and sadly, like so much such OS software, is poorly designed and has some very frustrating limitations, mainly in how it handles incremental backups with complete backups every xxx days. The other problem is that there is no automated restore but for the insurance cover, I'm prepared to accept the cost of a manual restore given that I've only lost one hard drive in more years than I care to think about.
With good knowledge, they can be worked around.
Took me ages to get it to do what I needed but once done, can be forgotten about.
Cobian Backup | Download Cobian Backup software for free at SourceForge.net
If your needs are simple, then I echo previous posters recommendations on Windows Backup and SyncToy.
Cheers
Simon