Watch newegg for specials. Over the last couple of weeks I have seen 3.2E procs for $200 or so, and IC7-G mobo's for $120. I have built 4 systems this year, all had IC7 series mobo's. The IC7-Max 3 can actually handle up to 6 SATA HDD's I believe, which is PLENTY of storage even using RAID 1. (ALL of the SATA ports on the IC7-Max 3 have RAID Controllers, so you could set up 2 RAID 1 groups (file storage and boot disks) and one RAID 0 for media manipulation.
Just make sure to get a shiatload of fans..