Your going to have to counter in Hard Drives , Personally I hate RapidLeech. Think about the I/O rape it going to do your drives.

Here is what I would get :

Intel Xeon either a 3440 or a E31240

2 x 1TB / 500 GB HDD SATA 2 7K Drives ( If you got some cash on ya get SAS 15K's )

8 GB RAM YOU NEED DDR3 !!!
good port connection