I'm getting my MacPro on Tuesday with 4 500gb drives. I am a digital photographer so it is pretty important to backup my data. Currently I have been using an external 2 bay setup with two 400gb drives. I didn't have them setup in a RAID configuration but had the same data on both drives. So basically I have 400gb of older data and 4 new 500gb drives to work with. I figured with the new drives I could get rid of the external setup unless anyone sees a reason for me to keep it. My initial thoughts were to have two drives in a RAID configuration and my mac operating system/applications on one with Windows on the fourth. I don't plan on doing a lot with Windows so I could partition one drive and use the other three in a RAID. What would be the best configuration for my needs?