Heya,
An easy and fast solution would be to get an eSATA controller into the system. Then just buy 1tb external eSATA capable drives. Connect. Backup. Disconnect. Store. To be safe, like others mentioned, do more than one backup set so that you double your failsafe in case something happens to one of them and don't store them both in the same place either. Doing this, HDD's in proper storage can last longer than you should ever need (ie, longer than your life time). Since you claimed about 1tb a year, you can easily get two 1tb eSATA drives each year. Right now, they're barely $100 each. $200 for a full double backup each year is pretty sweet considering it all. Think of it like $17 a month (the equivalent of an online MMO subscription). I mention eSATA because it's easy to connect, but mainly because it's so much faster than USB options and keeps you from getting inside the case (where you could potentially do something on accident and do damage). eSATA is as fast as if the drive was internal, so it will do very well for you.
You don't even have to get external drives. Another option is to just get a good eSATA capable enclosure, and buy internal 1tb drives. Just install the drive into the enclosure; backup; remove drive; store it. Replace with next drive in the same enclosure, and repeat the process. You could probably get better warranties this way as warranties on basic internals are longer served than warranties on external 3rd party enclosures with a drive inside.
I would not use RAID at all for this. There's no point. RAID is not about backing up, it's about uptime. RAID1 will not help your data either, again, that's just uptime.
If you plan to serve it all from a source one day, I would not serve it from your physical backups. Instead, just copy the backups to your own NAS and serve it that way, again, keeping backups separate from that. The NAS can run RAID all you please (RAID5 would be a good way to do that) and serve your data perfectly well. But again, this is not your backup, that's just your server. Keep your backups separate. It is more costly, but trying to keep years of data on any RAID array is asking for you to lose data. So make sure you do a real backup and keep it separate. Any thing you keep in use should be separate from backups.
Here's an example of the external eSATA (and USB) external 1TB drive:
$120 @ NewEgg
Very best,