Some battles don't fit in specific categories. For instance, the Betamax vs. VHS format wars of the 1980s were reenacted during the past decade in the struggle of HD DVD vs Blu-ray. Introduced in 2000, the next-generation optical discs from Toshiba and Sony promised better quality and more storage density. Though Microsoft placed its bets on HD DVDs in 2005, it was clear by 2008 that Sony's Blu-ray technology had the edge. In 2008, Toshiba finally announced that it would stop making HD DVDs. Don't consider the Blu-ray format a safe long-term bet, however. Digital downloads are eroding optical media sales, slowly and steadily.