I've just been reading Ray's newsletter issue #32-2 about File backups vs. Disk Image clones
Ray and dlwolff0 have got it dead right and I also do this, trouble is it takes ages but has got me out of big trouble several times.
I use Norton Ghost (my favourite) and Acronis Disk Image and they are both good.
In order to reduce the time to do backup/clone you might like to try this method with Norton Ghost.
Firstly don't run Ghost in Windows - create the boot disks as appropriate to you system and run Ghost from them
Secondly hardisks are now so cheap clone your C drive to another Harddisk
Thirdly - to speed things up take the IDE cable off your cd/dvd drive and fix it to your new hard drive (your computer thinks it's now a cd/dvd disk)

Doing it this way will cut time taken from (in my case) twelve hours to just two hours.
and when your box goes wrong simply whip out the old drive put in the new and away you go and that takes all of ten minutes but as dlwolff0 says your cloned disk is only as good as the last time you cloned it and is not a replacement for everyday backups

Their is a easier way to back up your hard drive. Using Acronis (I have ver 8.0) make a cd rom boot disk. After you do that reboot your computer (may have to goto your bios and make your cd rom boot first) then choose clone disk.

Follow the guides and backup your drive C or what ever drive you want to back up. I'm running win xp pro and the whole process just takes 7mins not 2 hours!!

My drive C is NTFS, my backup computer is FAT32 and it takes 10mins to backup.

You can not backup any hard drive while still in windows, you have to be out of windows!!!
no drivers can be loaded, thats why you want to make sure that cd rom boot disk to bootup first
so you can make a full backup of the hard drive. Don't get me wrong you can backup your drive while running windows but it won't be a true backup.

I been doing this for a very long time and it has saved my a** more than once.
Whats neat about this is your backup is as old as you back it up (every 2days etc.) depends on how lazy you are. Just take the backup drive and replace it with your old drive C and it boots right up. Your only out of date as to last time you made that backup!! Hope this helps someone out.......

Drive C & D WD 250gig drives

Have you heard of Shadow Protect? I've heard this is an excellent image program. A little pricing but I am trying the 30 day version right now.