Tape/DVD Backup Suggestions?

I'm looking into new ways of backing up the data in our lab, including
the PostgreSQL database. Currently, we have a single DDS-2 tape drive
capable of holding 8Gig compressed. However, it is slow (i.e. takes a
day to backup about 40 Gig of information), spans multiple tapes, and
makes it hard to find just a single file or two on the backup (i.e. I
have to go through many tapes before I can find and extract one of two
files).  Our CDRW backups are easier to manage and relatively fast,
but require dozens of CDRWs.

Can anyone make suggestions on backup systems? I was thinking that
some sort of DVD writing system would be good for accessing one or two
files in the backup quickly.  It would probably also complete backups
faster. However, I think DVD's only hold a few Gigs on them. Are there
systems like with these features that could handle say 20 Gigs per
media?

Thanks.
-Tony