Currently, all of the buzz seems to be focused around SANs and large-scale backup schemes. While these are nice...
and would be wonderful to implement, these high-cost solutions are not always feasible to everyone at this time.
At the very least, I would suggest that you first ensure tape backups are being done on a regular basis (nightly). I do not know how many stories I have heard of situations that could have been avoided by simply doing a regular tape backup. Make it a routine to schedule a job that runs a tape backup whenever you have the time available, and check for its successful completion every morning -- verifying that all is working correctly.
Changing tapes can become routine and it can begin to be something you take for granted. If everything is working smoothly, they are never needed. The one instance that they are needed is going to be the time you find out they are not as complete as you thought. It usually turns out to be something that could have been easily avoided with a little attention to detail and a conscious effort to focus on the backup procedures and tape management.