I've acquired a new netbook without an optical drive or recovery disks and want to image or clone the hard disk for a recovery option. I've got an external 1TB HD, but the lack of an optical drive ...

I'm upgrading the hard drive of a friend's laptop, going from a 160GB drive to 1TB. I would ideally like to image the old disk onto the new one. What's the current favourite for (free) disk imaging ...