Well, even though I have ~50 TB of storage so far, I went a different route than most of you folks, I just run Windows 7x64, EVGA x58 board, in a Coolermaster HAF case . I have two five 3 1/2 drive 3 bay hot swap cages in the case, hooked up to the onboard intel and jmicron ports. The boot drive is a Revodrive. If I ever need a dvd, I hook up an external. I have a low end ATI/AMD 4550 hooked to my monitor, plus my receiver, going to a 46"TV, I am able to watch 1080p, while downloading 15 threads from usenet at the same time, no problem.
Of course, I just don't have redundancy, since I don't use use raid, I just swap the 65 hard drives in various sizes in or out as needed - about like an old 8-track tape player from the 1970's. I have some drives goign back to 2001 still in use. To keep up with where everything is, I use the Whereisit database program. The drives are sitting in a bookcase, numbered on the end with a silver Sharpie pen. I figure these drives will last a LONG time, since the only time they get power is when they are in use.
I did lose a drive a couple of years ago, a WD400. None of my data is irreplaceable though, and I can probably find it all on usenet again if needed, since Giganews has an ~850 day binary retention now. Even two years ago, I was able to eventually find everything I lost on that drive that went bad.
I thought about a rack, a Chenbro or Norco case, and Home Server - but even with the largest Chenbro, I could not keep all my drives in it, so there would be no point. I also don't have to worry if MS has really killed the usefulness of Home Server.
I can't really afford to add a 4U case plus a few 2 TB drives every few months either. Of course, I envy those of you who can