Optimal Hard Disk Setup

[b]Hardware:[/b] xServe G4 1Ghz 2Gb Ram 4 UltraATA 250Gb Hard Disks I don't believe this model has a Raid 5 card. [b]Software to be installed:[/b] Mac OS X Tiger Server 10.4.7 [b]Purpose:[/b] Store large files (graphics, etc) so that the Mac dept can connect to the server and use the files from there rather than locally. [b]Network[/b] 100 Base-T but could move up to 1000Base-T [b]My Question[/b] What's the optimal way to set up this system (i.e. mirror, raid, etc). Thanks to all in advance.