If you are serious and willing to do some work learning how to use the software (and buy the hardware and software), get yourself a program called retrospect. it used to be made by dantz, but emc bought them over. it is superb, but there is a learning curve involved. You could also go for acronis, but you have less options, although it is a well respected piece of software. I use retrospect to backup all our data, and acronis to backup the system (windows installation). Also, partition your hard drive if you only have one, and keep your data on one partition and windows installation on another - that way, if windows crashes you can reinstall and your data will still be on the data partition. Even better - install one hard disk in your machine on which you will install windows, and another on which you'll keep your data.
And as mentioned above, you need an external hard drive. Get the biggest one you can afford.
We run a business and use retrospect to backup to multiple hard drives. Some are on site, and some are kept off site.
IF YOU'RE HARD DISK DIES AND YOU DON'T HAVE BACKUPS, AND YOUR DATA IS IMPORTANT, YOU'LL BE SORRY YOU DIDN'T BACKUP
Unless you only have a very small amount of data, forget about backing up to dvd. In my experience, dvds like to become corrupted. If you do back up to dvd, then make sure you get a copy of unstoppable copier (I think that's the right name anyway - it has recovered a few dvds for me).
Hope this helps.
