According to an article at DigiTimes, quotes for 16x DVD burners have continued to fall during the 2Q of 2006 due to competition from manufacturers like Foxconn Electronics and NEC.
The quotes for 16x DVD burners have fallen 5-10% during the second quarter of 2006 amid competition from makers such as Foxconn Electronics (the registered trade name of Hon Hai Precision Industry) and NEC, according to Taiwan-based optical disc makers.

Sources said Foxconn was competing for orders by initiating a price war for the 16x DVD burner segment while other sources said NEC was strategically dumping products to clear out inventory, causing market quotes to sink to a new low.
The article also mentions that several manufacturers are shifting to "Super Multi" drives or 18x DVD burners to raise their average selling price. If you'd like to read more, head on over to DigiTimes.