Just a quick point on RAID 5 vs. RAID 1. When I first started this venture, I really thought RAID 5 was the way to go. I've since given up on the idea of RAID 5 and am going to go RAID 1. I really don't think RAID 5 makes much sense at this point for consumers.
Why? Because RAID 5 really isn't going to be cheaper than RAID 1 for the purposes of audio storage for even those of us with some of the largest collection. Then there is the complexity and higher failure probability of RAID 5 vs. RAID 1 and it really isn't worth it.
Let's break it down. Let's say we are going to go with 300GB drives and a street price of about $160 (give or take $10). Now consider that RAID 5 cards are about $200 for cards that support up to 4 drives. 8 drive cards are in the stratosphere still, from what I've seen anyway. From a back of the envelope calculation you will see that 300GB will store about 800 CDs in FLAC. So 4 300GB drives with a RAID 5 card will cost $840 and have 900GB of useful space, which will hold ~2400 CDs. 900GBs in RAID 1 will cost $960.
So RAID 1 costs a little more, but not really that much and 2400 CDs is a pretty large collection. I think the couple of points that make the price difference moot are as follows:
1) With RAID 1 you can buy drives in pairs as you need. It is going to take quite some time to rip 300GBs worth of CDs so when you get around to needing more space that $160 will have dropped some already, or atleast bigger drives will now be in that price point.
2) Although RAID 5 technically allows one to grow the array as needed by adding on another drive, real world trials by very tech savvy guys I know how proved to be nightmare-ish. I have heard story after story about people loosing the entire array while trying to expand the array. And don't even think about software RAID 5! RAID 5 also requires you to have all the same identical drives, so you are going to have to plunk down your cash now if you want to be sure to get your drive while they are still easy to obtain. With RAID 1, you only have to match pairs, so secondary pairs can be whatever's cheap and easy at that time.
Oh did I mention that RAID 1 cards are cheap, and many mobo nowadays even have built-in RAID controllers?
In theory, RAID 5 seems like a great solution, but in practice for our application I think it isn't quite as nice as it first seems.