The above answer summarizes things nicely. I would add a couple of general comments. With the exception of holographic memory, the lowest cost per bit for storage is undoubtedly magnetic tape. The highest density, most reliable tape drive would then logically be the best choice. In most cases, it will be faster to replace the drive than to try to extract a jammed tape of either sort.
Magnetic tape has relatively slow access, but fairly fast transfer rates once the file is located.
Optical discs of various types have fast seek times but slower transfer rates. In favor of optical disc is it's media reliability and large number of vendors of standard media and drives. They are NOT compatible. DVD-RAM is widely available now with several drive vendors in the market. Consumer DVD-RAM drives are more like consumer CD drives and would likely not stand up to archive operations for any length of time.