For those who are not familiar with tape, LTO is the current technology. It is a vendor neutral/open standard, unlike DLT (Compaq), AIT (Sony), DAT (sucked), Mammoth (Exabyte), and others. Basically, it got commoditized after a long long fight to keep prices high and customers locked in to certain vendor technology.
I would really like to hear what people know about this process of standardization with tapes. It took forever for this to happen.
Because every tape and autoloader has been so different, it has been really hard for software vendors to write applications to support this huge number of libraries. Just as an example, Bacula, one of the most popular open-source backup apps out there has no support to eject a tape. I kid you not, if you use Bacula, you gotta bust out the mt eject command after telling Bacula to release the tape.
The great thing about LTO is that they recently added hardware encryption and partitioning in LTO5, along with a density increase. I don't know what the current status on LTO6 is, but I don't expect to see anything for another year or two. LTO5 just came out one year ago.
DLT S4 was keeping the density war up with DLT4 (800GB native), but Quantum killed it back in 2007 and there will not be a DLT S5. Anecdotally, I have a lot of trouble with my at-home DLT S4 drive that I've never seen with LTO3/4 drives. The problem seems to be that some tapes just go bad after awhile and despite Quantum's "lifetime guarantee", they will tell you to go f-- yourself if you try to RMA a two year old tape with four or five writes on it.
The one notable exception to this commoditization is Sun/Oracle's StorageTek T10000 tapes, which are something like 5TB. However, Oracle is not a research company; they will eventually just go LTO too is my guess. They already make LTO stuff.
Personally, I have a Quantium DLT S4 drive for my home backups, along with a small software RAID array that does nightlies. It has the benefit of being able to store everything I've got on a single tape. I use a custom script with GNU tar.