Glad to see people here talking and thinking about archiving. A year or two ago, I went through the process of developing and implementing an archiving plan for all my electronic data - personal, my other hobby (field audio recording), and now photography.
I don't think I'm addressing any specific questions, necessarily, but hopefully my comments will prove useful to others. I think an effective archiving plan includes two primary considerations: redundancy and backup. The question only you can answer: what plan provides sufficient redundancy and backup
for you, based on your requirements - cost, ease of use, risk sensitivity, etc.
I think I approach this much the same way as jmdeegan...
Redundancy
Redundancy provides the ability to recover quickly, with minimal effort, in the event of a single-point failure like a HDD crash.
For redundancy, I mirror all my data nightly. For example, every night I ensure all the data on physical drive A is mirrored on physical drive B. For my purposes, nightly is frequent enough. I don't use RAID (real-time mirroring) for two reasons: my critical data doesn't change enough by the second / minute / hour to warrant real-time mirroring, and in my experience consumer-level RAID, while inexpensive, isn't terribly reliable. Instead, I use
DeltaCopy to nightly mirror one drive to another. This way, if a single HDD fails, my data is safe, I buy a new HDD to replace the dead one, and then re-mirror.
Backup
Backup provides the ability to recover (typically more slowly) in the event of a systemic or catastrophic failure, like multiple HDD crashes or a house burning down.
I backup all my data on optical media, mainly DVD, though I still have a few CDRs I haven't migrated to DVD yet. These DVDs provide the ability - albeit slowly and time-consumingly - to recover all my data if the redundant systems fail. As someone else already mentioned: it's crucial to store optical media in an appropriate environment to mitigate risk of media failure.
Finally, I backup all my data quarterly onto HDD and store it off-site (at a family member's house). In the event of catastrophic failure at my home, e.g. my house burns down, I'll still have reasonably current data (within the last 3 months). If catastrophe strikes on the day before I perform my regular updates, I'll have lost 3 months of data. This is acceptable to me based on <a> the relative (un)likelihood of catastrophe striking, and <b> the fact that I'll have significantly bigger concerns than data backup.
Edit to add: LaRee - I think you're on the right track, ensuring you have multiple copies of your data. As with many things, I think the key is to develop a system that works for you and then exercising diligence in executing and monitoring the system.