I use a RAID5 setup with 4x WD Caviar Blacks on a dedicated RAID card (Areca 1222 PCIe).
This array of 4x1TBs gives an effective capacity of 3TB, and transfer speeds are extremely fast as the controller accelerates RAID5 operations in hardware with none of the overheads in processing incurred by using a software RAID solution (as commonly found using on-board motherboard controllers for RAID). It also has a 128MB cache on board.
The Areca is a joy to work with, it's an expensive card but very robust and intuitive to set up.
You can split the array up how you like so they appear to the machine and OS as more than one "drive" if you like. For example, my 3TB array is split into two "drives", one 120GB for operating systems, and the rest as storage for programs and data. This is useful for situations where the array size is too big for an MBR partition scheme, or where setting up a multi-boot environment with lots of extended MBR partitions could be a headache to get working.
The card has a web interface accessible via the driver to configure and monitor it, and also has an Ethernet port so it can be accessed from another terminal on the network, but also broadcast warnings and other information to wherever an administrator may be monitoring.
I chose the Areca for its excellent driver support; it has drivers for all flavours of Windows, both 32 and 64bit. Linux support is in the kernel, and MacOS X has support for it built-in for use in a hackintosh application (
) or for use in a Mac Pro.
It is a server-class card with tons of features, and probably excessive for a home machine, but I can recommend it.
