What types of drives do you use on your servers? SATA, SCSI? Are they in a RAID array or just individual drives?

Currently we have 2 individual SATA drives in each server not in a RAID configuration. I think I am going to push for RAID though as with working in my regular office with it, this has saved me a couple of times in the last few years to the point where the users had no idea a drive failed because I just swapped a good drive in with out switching off the server.

What are your experiences with restoring and drive reliability?