What exactly do you mean by imaging? If it's as answered simple ISO/CD imaging, then I just mount whatever I need with the mount command in Linux (mount -o loop image.iso /path/to/mount/point) and in Windows, use Deamon Tools. If it's for drive imaging, as solutions like Symantec Ghost and Windows Backup offer, then I think FOG is the best one for larger scale operations and I use Clonezilla at home.