I would consider using RAID 5, so that your server can survive the death of a single drive.
Read the article on modifying XP to create a software Raid 5 array.
This weekend I am buying a fourth $120 WD1200JB for $40 (after $60 rebate) for my software Raid 5 array.
Why. Because I am too cheap to spend $90 for a RAID 5 controller and I am too lazy to backup 320 GB as often as I should.