It's a sad thing that has happen to a friend of mine and i just cannot imagine being in his shoes. I'll snap and may just committ sucide if i were him. He just lost 10 years of photos he painstakingly took, photoshopped and even converted from film into digital and now, it all crashed. I'll preach this again, please do yourself a favour, build a raid machine. Harddisk are so darn cheap nowadays, it's well worth it. The argument here is not that "luckily he still have his films or film scans, it's he has since gone digital for a while now and lost everything. no DVD or CD archive for the past 5 years at least. Imagine if there was your first new born, photos all gone. Your newborn's first step caputured beautifully in digital photos, call gone. I'll really die.
I've recently upgrade this machine I wrote about and built another exact same one recently to a full RAID 5 machine. Software raid or onboard raid chip whatever, it works and it has proven fine for a long time. I've even tried purposely failing it, rebuilding it is peanuts.
So please! Build a raid machine, it won't cost you much and the benefits are just beyond money can buy.