This is an issue that was hit home to me last week when my main machine contracted a virus and crashed. After multiple attempts at recovery, I was forced to reformat my main drive and re-install my OS. Fortunately, I had taken precautionary measures against such a catastrophe and came out of the incident relatively unscathed. Here's a brief description of my backup system:
1. After filling a card with photos, I import it into lightroom on my main machine. I keep all my photos on a separate Western Digital 1 TB hard drive on my machine both to avoid bogging down my computer and also to avoid losing everything in the case of having to re-format my main drive (which is what happened last week).
2. I set the card aside and avoid re-formatting it until I've backed up the photos onto an external drive.
3. I have two 1 TB external drives that I backup everything to. One of them is an iomega (Check it out here), and the other is a LaCie Rugged Hard Disk (Check it out here). Both external hard drives are stored in a separate location from my main machine to ensure added security.
4. I also carry a thumb-drive with me that has backups of important documents, photo editing presets, a handful of my favorite images, etc.
If you value your images, you'll seriously consider investing a little in a backup system. It has saved me a couple of times now, and I'm very grateful.
Scott Kelby also gives a brief look at his backup strategy over on his blog. His is slightly more elaborate than mine, but it may give you an idea of how other professionals safe-guard against disaster. Check it out here.
