If that's all you want, I'm sure you can find a Windows equivalent to dd to run every day. Do a direct bit copy, and then your external disk will always be in sync with your internal disk.
That's a terrible idea. Backing up with disk images will take a long time, erase your previous backup at the start, and not prevent against filesystem corruption.
Should Checkout CloudPull for the mac for backing up google services. Yes, everyone should backup gmail. If you get hacked and all your email deleted, googles backups won't do you any good.
Arq is a good backup-to-cloud service if you're conscious of where your data goes(S3) and who has the keys(Only you).
They're both indie programmers out of Boston too, which may be some of my bias, but check'm out!
