The Nintendo DS, DS Lite, DSi, and DSi XL have all contributed to the company turning a nice round milestone today. According to the NPD Group, Nintendo has now sold more than 50 million units of its popular DS portable console family in the United States. The latest hardware sales figures also show a 10 percent increase in 3DS sales in the month of September, up to 260,000, and nearly 450,000 3DS units sold since a drastic price cut was enacted on August 12th. While that may give it the US lead in terms of mobile gaming, it's still well behind the 438,000 Xbox 360s or approximately 370,000 PS3s that Nintendo's competitors managed to sell to home users during the month. Both those consoles are now growing long in the tooth, but buyer interest doesn't seem ready to abate. The Wii, whose successor has already been announced in the form of the Wii U, trailed in the charts with 240,000 consoles sold in September. So it's a case of a happy past, a tepid present, and an uncertain future for Nintendo.