I hope you take mirroring as an option. I dont run a system without my stuff mirrored. Even though I do backups. When a drive dies everything on that drive goes with it. With mirrored I can keep on going with no down time while I get the drive replaced.
And if you have TB's of data doing a nightly backup isnt going to be the best thing as it would take so long and you would need backup drives big enough. What ever is most important to you make sure to keep backed up and on a mirror raid drive setup if you can.
These are my drives. Setup in a raid 1.
http://www.newegg.com/Product/Product.aspx?Item=N82E16822136798 RAID-specific, time-limited error recovery (TLER)
1.2 million hours at 100% duty cycle
NoTouch ramp load technology
24x7 reliability
5 year Warranty
And for not being SSD it is one of the fastest drives I have found in the 7200 RPM range.
Shane