One of the manufacturers have a 500GB drive out and have announced a 1TB one.
As far as the backup is concerned, times you could use one tape for a single backup is long past. Backing up tb of data is now usually done on SDLT or LTO tapes. LTO drives get apr. 800GB on one tape using compression, on average you get between 400 and 600GB on a tape.
High volume user (like at our work) we use several (4) of these drives in a robot. But believe me, these machines cost more then my car!
edit: my windoze machine with aprx. 1GB of storage I backup on my DLT drive (40/80GB). That means swapping more tapes then I ever needed to swap floppy's in my miggy
And that is just my PC. Backup my firewall takes one tape, backup my exchange server takes 3 to 4...
