Mr.Playstation on 04 September 2014
Saw an article saying it sold around half a million, will try to find it.
Here it is, it was actually 1/4 of a million:
Sales
When the Xbox launched on November 21, 2001, the console quickly sold out in North America. In Japan, however, the console sold only 250,000 units. After its release in November 2004 Halo 2 became the best selling Xbox title worldwide, selling over 8 million copies, thanks in large part to the quality of its online multiplayer through Xbox Live. It was arguably the most popular online mutliplayer shooter on home consoles during the sixth-generation of consoles.
According to Microsoft the Xbox has sold over 24 million worldwide as of 2006.
