I want to make full disk images of different computers that I could later restore if something goes wrong. Also, being able to mount the image/access the backed up files would be really useful.
What are my options?
To make the image you will probably want to use Partimage
So that the image is consistent, you will want to make sure the disk is offline when you make the image.
I have transformed Partimage images into virtual drives for VirtualBox. It appears that you can also Mount a partimage file as a loopback device, but I haven't tried that myself.
Bacula is a free-as-in-speech linux backup program that allows bare metal and single file recovery. Also in its favour is it doesn't require an offline system to get a full system backup. It's a bit of a pain to set up, but the end result should be pretty sweet. The backup format is open source but Bacula specific. You need Bacula to access your backup.