Windows: Paragon Drive Backup Professional can image and back up whole drives or just important files, whether your hard drive is booting or not. Today and tonight, its maker is giving it away for free, along with future upgrade discounts.
Paragon's hosted free Drive Backup giveaways before, but this one appears to relate to a newer version than previously posted. Like before, though, Paragon offers a whole bunch of useful tools for getting your stuff secured for future failures, or brought back from a near-dead hard drive (with the help of a Linux-based live CD or thumb drive image). Paragon can also back up disk images to virtual machines, which is pretty nice for getting started back up with your old system right away.
Paragon Drive Backup Professional is a free download (until 11pm AEST, May 4) for Windows systems only. Thanks for the link, djbender!