Halo: Reach is already the biggest-selling game in North America this year - bigger than Red Dead Redemption, Mass Effect 2, Final Fantasy XIII, New Super Mario Bros. Wii and Madden NFL 11.
Halo: Reach managed 3.29 million sales by the end of September (launched on 14th), according to a Gamasutra report. That's double what Halo 3: ODST mustered in the same period (1.52 million) but equal to Halo 3 (3.3 million) which, remember, sold to a smaller installed base in 2007.
Halo 3 went on to sell 4.7 million copies across North American by the end of 2007.
The US best-seller chart for the nine months of 2010 ended 30th September was topped by Halo: Reach. In second was New Super Mario Bros. Wii, third Red Dead Redemption Xbox 360, fourth Pokemon SoulSilver and fifth Super Mario Galaxy 2.
Wii Fit Plus was sixth, God of War III seventh, Modern Warfare 2 eighth, Just Dance ninth and Wii Sports Resort 10th.
Note that this is a single-platform chart. The two multiplatform games - Red Dead Redemption and Modern Warfare 2 - were represented on Xbox 360.
Unfortunately, the only multi-format chart provided by Gamasutra was September 2010 US sales, which Eurogamer covered last week.