It's been an industry non-secret that manufacturers have had an easier time making dual-layer HD DVD discs than dual layer Blu-ray discs. Hence, 30GB dual-layer HD DVD media have already been on the market, beating the single layer 25GB Blu-ray discs by five whole gigabytes. But now Blu-ray has the last laugh as Sony finally gets the 50GB dual-layer Blu-ray discs onto hands of US consumers.

The 50GB dual-layer Blu-ray discs can hold four hours of HD content, and transfers at 24Mbps. They've got a built in scratch guard and "archival reliability" to prevent bad burns. Which, at $48 a disc, would be the most expensive coaster you've ever made. – Jason Chen