Best approach to Mac Server and Backup for small studio

This is my first post so please bear with me...
We have a small studio with 6 Mac Pros but no back up or server. I am making the recommendation to management. We are not technically strong here as well and are looking for simplicity. A fellow who handles IT for a much larger group uses this configuration:
mac pro / Apple Server unlimited
One 2.8GHZ Quad-Core Intel Xeon
2GB (2x1GB)
Mac Pro RAID Card
ATI Radeon HD 2600 XT 256MB

Also add a
LaCie eSATA PCI Card - For a faster connection to external drives.

3 1.5 TB drive and install them, set them up as follows
Drive 1 - System (the drive the mac came with)
Drive 2 - Partition; 50gb for system backup, the rest for studio work backup
Drive 3 and 4, RAID 0 (Mirrored) the working space for the studio.

For backups get an external Vantec NexStar MX eSata box with 2 1.5 TB drives and set it up as a RAID 1 (Stripped)

For backup software-Synk Pro. Another supplier had suggested BRU, however I am concerned that although it is built for enterprise, it is too complicated to administer.

 

Excellent suggestion..I will work it into my approach. What I didn't mention in my post I expect the artists to work either from the server or from there workstation, that will be up to them. We do have a gigabit switch.