Here's the thing about backups. If you have to do them manually, it won't happen and you won't have your data backed up when you really need it.
There are basically two methods I use together.
I use an online automatic backup service to save all my data files (no system files, no system image), and media files that I can't just easily download again from the source. I use sugarsync.com, and it's a paid service, and it works for me. You select the folders it should automatically backup, and the client just does it all the time, uploading files to the server as they appear, disappear, get moved or get created or get changed on your hard drive. It even keeps several versions of files if you want it to. I can access any of those files from anywhere in the world on any computer using a standard web browser. Typically, you would backup files on your desktop, anything under My Documents, etc, and things like quicken data files, etc, that might not live under My Documents. I also include My Pictures, itunes music libraries, etc, but no video. So I end up with all my critical data backed up on the web this way. If I lose the source computer, I still have all my critical data.
The second method is to get an external hard drive, a large one is preferable (where large is much larger than your c drive). and run a software program like Acronis True Image Home or even Norton Ghost (I'm sure there are others) or on a Mac, use the built in Time Machine software. Acronis and Norton Ghost let you make a boot CD that you can use for recovery. All of these programs let you create automatic unattended backup schedules, and they allow you to manage the amount of space dedicated to the backups. I do a monthly full backup and a weekly incremental backup. I exclude all media files from the backups, since they are all being backed up by sugarsync.com already, so the backups are relatively small compared to the size of the source disk and don't take that much time to create. Once you set it up, it all works unattended, but you should test the boot CD. You can restore a file, a folder or the entire disk using this method. The first time, you should do a manual full backup of everything (exclude nothing), so in case you miss a file, or other partitions on the disk, you can always restore those from the original full disk backup. Make sure you keep that backup separate from the regular monthly and weekly incremental backups.
Anyway, that's what works for me. Find something that works for you, and make sure you do it, automated if possible, and test it to make sure it works.
Of course, this is what works for me. I don't expect it to be the method that works for everybody. You have to develop a method that works for you and stick to it.
-David