"Redundant Array of Independent Disks"
Gotta love commercialization eh? It used to be "Redundant Array of Inexpensive Disks", but I guess there wasn't much money to be made with that acronym. (Yes, I know that this move was made in recognition of the fact that RAID arrays are implemented for performance as much as redundancy nowdays, so 15k SCSI drives are pretty much the standard).
Anyway, back to the topic at hand. For a home server, I'd cast my vote for RAID-1. Even though I run RAID-5 on my home server, I'm just nerdy like that and I think that's overkill for the average Joe.
One thing to consider that I haven't read (but might be posted already) is rebuild time. If you have a RAID-1 array and a drive fails, you can keep working. (At your own risk mind you since there will be no redundancy anymore). With RAID-5, you lose a drive and things come to a screeching halt until you replace the drive. (Which is also why I have a hot spare in my system)
Someone did mention it, but I'd have to second it - RAID arrays are not a substitute for backups. If you data is important, back it up. RAID only protects from hardware failures, not user failures, file system corruptions, viruses, hackers, etc.