Acronis has been in the backup business for a long time - pretty much as long as I can remember being interested in backing up PCs. I've been using their products for quite a few years - at least since True Image version 5 or so. It has saved me, and several of my friends, from disaster a number of times over the years.
The latest version of Acronis True Image has a number of interesting variations on what "backup" means. You can make an "image backup", which is essentially a copy of your disk or partitions of your disk, that you can later use to recreate an exact copy of that drive or partition. You can also make a backup of "system state only", which copies the system files, folders, drivers and such, without copying your data. You can also make a variety of "data or application" backups, based on folders (everything under My Documents, for example), file types (all pictures, videos, music and such) or backup your email (including folders, attachments, and address book), and lots more. There is also the option of excluding certain types of files, such as hidden files/folders, system files/folders, or specific file type extensions.
You can make the backup on just about any kind of media that you can imagine - CD, DVD, USB/FireWire hard drives, Zip/Jaz drives, network shared disks, and even FTP servers. If the size of the backup is larger than the capacity of the target, True Image will automatically partition the backup to fit on multiple volumes. This is fairly obvious in the case of backup to CD/DVD drives, but it is a nice touch that they also recognize when the target is a FAT32 disk drive, and will stay within the maximum file size limitations by splitting the backup into multiple 4 GB files.
Once you have made a full backup, Acronis gives you the options of making either "incremental" or "differential" backups. The difference between the two is the amount of data that typically needs to be backed up and the amount of effort it takes to restore.
In addition to the obvious use of a backup archive - restoring it to a new computer or disk - Acronis also includes tools to let you explore an archive from within the True Image program, and to actually "mount" the image as if it were removable media, which you can then copy files and folders from with normal utilities - a very nice touch when what you need to do is recover just one file or folder.
True Image Home also includes backup scheduling capabilities, to run automatic unattended backups at specific times, days, intervals or based on system events such as log on / log off. Combined with large capacity backup media, such as USB disks or network storage, this makes it very easy to ensure that you are well prepared in case of accidental file loss or catastrophic failure. My own installation at home is a good example of this. I have a laptop computer and my partner has a desktop, and we are both connected to a Linksys WRT350N router with a shared 300 GB Iomega disk on its Storage Link USB port. Both PCs are backed up to the shared disk on the router. After making the initial full "disk image" backup, I set up a True Image scheduled task on each computer to make an incremental backup every night, and a differential backup once a week. There is one small "trick" here; if you are backing up to a network disk, and it has a FAT32 file system, Acronis has no way of knowing that, and therefore no way of knowing that it should split the archive into 4 GB pieces, so you have to specify that manually. I made several failed attempts at full backups before I realized why it was getting a write error after processing for quite a while.
Finally, True Image Home includes a number of very useful tools and utilities. There is a "disk clone" utility, which makes it easy to move to a new disk if you run out of space, and an "add disk" utility, which is a lot easier to find and use than the Windows Disk Management utility when all you need to do is format and partition a new drive. There are also tools for secure, complete deletion and cleanup of files, folders and entire partitions or disks, and for general Windows cleanup tasks such as cleaning out temporary files, remnants of past file and computer searches, and so on.
I strongly recommend Acronis True Image Home to my friends and family, and it is always one of the first things I install on a new computer, whether it be my own or one I am preparing for someone else. It is by far the best $50 investment you could ever make on your computer.
I'll close this with an example of how True Image "saved the day" recently. I prepared a new laptop for a friend, and used True Image to transfer all of his user data and then to clean up the old laptop so he could pass it on to someone else. A couple of weeks later I got a panic call - the new laptop had been stolen at an airport. Of course I had made a backup of his user data on a portable USB drive - but he had been carrying it in the same case with the laptop (BIG mistake!). However, when I had transferred the data, his USB drive had not been large enough to do everything at once, so I had used an extra drive that I had laying about, and then made a partial backup on his drive. I had not needed that drive for anything else since then, so the image of his laptop was still on it; I was able to restore the user files from it to DVD-R's, and then mail those to him.
If you aren't performing SOME kind of backup on a regular basis, you are headed for serious trouble, sooner or later. If you're using something other than Acronis True Image Home for backups, you're probably working too hard, so you should check it out.