Archiving doesn't need to be complicated or expensive. You just need to establish and maintain a set of protocols. My suggestion is to automate as much as possible, and have two backups with one off site (and preferably one read-only). Whatever digital system you settle on expect it to change - often. You need a simple, scalable solution that doesn't lock you into any particular brand of operating system, software, or hardware vendor.
For books on DAM there are two I can recommend:The DAM Book
by Peter Krogh and Digital Photographer's Guide to Media Management
by Tim Grey.
Peter's is the source most often referred to, and Tim's is a lighter read with some different view points. With both books look at the underlying ideas rather than how the featured applications work.