Well, technically it's faster, particularly when writing large files to disk. The speed increase really isn't noticeable, from my experience, and most people will tell you that. It's more of an enthusiast thing. I like to run the best, latest hardware, and I got an okay deal on the drives.
The mobo, memory and processor was over 800 w/ tax and shipping. The Velociraptors were 300 shipped from another forum. The rest you can find at newegg. I'd say everything is worth close to two grand.
Im using stock cooling, but they have gona up a bit (I kinda cracked the thermal paste)
Its just how ive setup my fans. I put an intake fan blowing directly to the CPU. But on that fan, i attached that plastic funnel inlided with the case ( so it blows exclusivly on the CPu)