Maxell hints that it will ship 300 GB optical media next year, in September 2006 to be more exact. The bandwidth is decent too: 160 Mbps. The technology behind all this? Holographic storage:

Holographic recording technology uses intersecting signal and reference laser beams to store data in a number of 3D holographic images.

According to Maxell, one 13cm optical disc can store up to 150 million pages — more than 63 times the capacity of DVD. [...]

The technology also has an impressive lineage. Hitachi-owned Maxell is working with InPhase Technologies, a subsidiary of Lucent, which has led development of holographic media.