Backup?

I am looking for a good solution to an ongoing problem. I work in an engineering firm that uses AutoCAD and MS Office software. If you have ever been in this type of environment you will appreciate where I am coming from. My delima is trying to keepup with backing up our 9 servers, archiving closed projects and also restoring those accidental deletions and elusive missing files or folders. My question is how would you design and accomodate these needs with as little administrative action as possible? We are currently using an 10 magazine autoloading tape device. I am toying around the idea of NAS/SAN, HSM and RSS.