I will chime in again on storage....for those that read past "tomes", feel free to bypass my comments.
Completely concur with folks suggesting OWC for drive cases and good deals on drives. Just built two more of the Elite-AL cases (FW 800/400 and USB2) with two 500GB Maxtor Maxline Pro drives in each. Each drive in one case gets backed up to a drive in the other case, rather that use any RAID. This ensures two copies that you make or schedule to be made as needed. So if you accidentally erase a file or directory on one, you still have it on the other for slavage until you update the copy. The OWC cases are very good, quiet and well made.
For the RAID side of things, the Infrant Technologies NAS system stuff is hard to beat, unless you want to spend a whole lot more for mission critical stuff. Setting up on a gigabit switch is the way to go, as already mentioned. Another RAID option is HighPoint and their RocketRAID controller cards and X4 cases. They are blazingly fast, but the fan noise is a bit more than the OWC or Infrant devices. They are also dedicated SATA connections, hence the greater speed. I use it as my processing drive in a RAID 5 configuration, then once a project is completed, I move it off the RAID 5 and onto one or more of the OWC set-ups. Gives me speed and on the fly back-up while working, then separated back-ups once moved to other externals, where they are more archive, but still readily accessible.
For HDs themselves, go for Maxtor (now Seagate) and Hitachi, and WD. There are some differences within some of the lines, such as the Maxtor 500GB Quickview versus the Maxtor 500GB Maxline Pro. The Quickview were designed more for TiVo type applications, while the Maxline Pro are more "enterprise capable". Difference of a few bucks, but it may or may not matter to you.
No RAID is safe without another back-up of some sort. Even the RAID 5 stuff could experience two catastrophic drive failures before you replaced a bad one, and then you are toast. However, most drive failures are going to happen sooner than later. Best advice is to burn a drive in for several days running before starting to use it for critical storage. Bill's concept of buying refurbs works here, as those drives are usually stable by that point.
If you want to get into HD performance, go check out the various tests posted on
Real World Speed Tests for Performance Minded Mac Users They put things through the paces and report quite candidly on things.
I have no affiliation with any of these folks....I just have and use a lot of HDs for lots of storage....experience is a good, but often brutal teacher.
LJ