No, RAID-0 has no redundency what so ever, if one drive goes down, the whole array would go and all data on it (well 1/3) would b lost. So from what i seen, u wanna mirror (RAID-1) 2 drives, u cant mirror 3 drives cos like u said u need an even number, so u could mirroc 2 of the drives, and use the other as a on line spare (as i said i aint too fimalir with IDE but with SCSI this can be done) then if one of the drives went down, the online spare would kick in right away and start reconstructing the array. This would give u only 60GIG out of a possible 180GB but is the best for data protection like u say is vital. i just dont know if u hav the abality to make your spare hard drive as an online spare.