Question : Problem: Lowest cost way to backup large files.

I want to store large video files on some sort of hard drive array so we can play them on our media sever.  I have been considering a RAID 5 system.  Ill have all the files backed up, but since there will be a lot of time invested in getting the videos converted to the correct format I dont wont to lose the files.  I always thought that RAID was the greatest thing since sliced bread until I had a computer that lost a motherboard, and I could not get my data off the RAID as you can a normal hard drive.  I kind of lost that secure feeling about having a RAID.  Is there some RAID systems avoid these hardware issues?

Since the files wont change is there some kind of software that can create a virtual raid.  It could build the parity info only when the new data is added, but if your hardware failed you could still read the data off the drives?  

Answer : Problem: Lowest cost way to backup large files.

Either iSCSI NAS box or SAN storage.

My personal best pick is the iSCSI NAS, and today there are lots to choose from but my favorite is SnapServer.

If using the iSCSI then add a dedicated NIC that does TCP/IP offload processing on the card.
They are called TOE NICs and cost a lot more but well worth it for the improved performance.
If going with SAN storage you don't need a SAN just an HBA.

Here are some sample offerings
http://www.snapserver.com/snap/en-US/Products/
http://www.dell.com/content/products/compare.aspx/network_storage?c=us&l=en&s=bsd&cs=04&ST=san%20storage&dgc=ST&cid=19862&lid=542988
http://www-03.ibm.com/systems/storage/disk/index.html
http://www.hp.com/sbso/serverstorage/nas.html
http://www.hp.com/sbso/serverstorage/san.html