Where to start...RAID...LVM...

[everestx]

Hardware raid is as good as it gets. Software raid can be extremely difficult to recover.

Something to keep in mind is how much totall data you are storing. For many people, a raid 1 mirror is as simple and proactive. It will mirror the disks in a 1 to 1 backup, you can litterally take the dead one out, swap the 2nd drive, and there your data is. If you have around 2tb or less, this might be the easiest and least labor intensive way to manage your data.

Personally, I prefer mixed raid arrays. While it's a bit extreme it gives me crazy amounts of flexibility.

In my case, once the raid controller arrives I will have my OS on a raid 1 (1 to 1 backup), my download & testing directory on a Raid-0 (no redundancy, but it's fast for extraction, replairs, etc), and my storage array will consist of 6 1.5tb drives in a raid 5 array (striped array with redundancy).

I'd advise looking at the Dell Perc 5/i, it's around $150 on ebay with battery backup and ecc ram. (Side note, on the perc cards /i is for internal, /e is external) Additionally, these are acctually repackaged LSI megaraid cards, that you can reflash to thier full potential but it's completely unsupported by either manufacturer.