Newer Ultrium versions and autoloaders...
The reasons that tape still dominates most backup scenarios:
* The drives and autoloaders aren't that expensive really - about the cost of a typical low-end server (2-3 grand), despite what one poster said. The cost of tapes is perhaps actually a little high (especially when you have to buy 30+ of them in one go).
* The Ultrium standard has been getting faster and higher capacity with each generation, so we're getting to the point where you can backup quite a lot of servers across the network on just one tape (though you still want an autoloader if you want weekend backups or your backups use 2 tapes a day).
* You can physically take the completed backup tapes to an offsite safe in case disaster recovery is needed (main machine room explodes or whatever).
For me, backups to disks *only* work sensibly if you have a high speed (gigabit preferably) Net link to another location where you actually keep the servers with those disks (i.e. a DR location). You can't just backup to a big-disk server that's in the same machine room as the one the servers are in because your backups will be non-existent if the machine room explodes and there's your business dead in the water.
I think it's the cost for an SME of setting up a DR location with a server and a load of big disks is why tapes still rule the roost. And if you want to be really safe, you'd need at least dual-homing too between your main site and the DR so that you can always get at your backups at the remote location. All of this costs time and money to set up.