Basics of RAID
Doggie Fizzle writes "RAID has been common in business environments for ages, and is now becoming more viable and popular for personal computers. This article focuses on the the basics of RAID, and spells things out for beginners or tech veterans. From the article: 'The benefits of RAID over a single drive system far outweigh the extra consideration required during installation. Losing data once due to hard drive failure may be all that is required to convince anyone that RAID is right for them, but why wait until that happens.'"
Alternatively to DVD backups, you can also sync up your data on a regular basis to an external hard drive. This doesn't protect you if your house burns down, like DVD backups kept in a safety deposit box would do, but it does help you restore lost data after it gets corrupted.
Ultimately, all these solutions require varying amounts of money, time, and effort, so you just have to decide what level of security you require and what you are willing to pay for it.