But then of course, there's the RAID issue. If you haven't made ny decisions on this front, I would really recommend you go for the following set up (I have one and it has made a light-year difference in how footage is processed. Let's put it this way: I no longer have to watch paint dry.
1 x Enhance-Tech E800MS 8-bay Cable-less Enclosure with quiet PSU and fans
1 x Areca ARC-1880x SAS RAID Controller Card
8 x matched 3.0 TB Desktop Edition Drives
2 x 1m miniSAS to miniSAS Cables
Speeds of 900MB/s. Good luck with it.