We reported last week that Halo 3: ODST had sold around 2 million copies in the first 24 hours according to early data. Well now the final data is in and the original figure of 2 million was a little high - day 1 sales were in fact closer to 1.8 million copies but during the rest of the week, ODST managed to sell a futher 400,000 copies to take the total sold as of the 26th to just over 2.2 million units worldwide.

Highlights include over 1.7 million in the Americas, 230,000 in the UK, around 50,000 in France and over 20,000 in Japan. Comparing directly to "week one" sales for other Xbox360 games, ODST finds itself in third place:

It must be noted however, that Gears of War 2 released on a Friday compared to the Tuesday release of ODST so the "week one" totals for the games listed above include two days of sales for Gears 2 and five days for ODST. Comparing over the same timeframes, Gears of War 2 is actually just ahead of ODST at both two days and five days, therefore ODST really sits in fourth place behind Halo 3, GTA IV and Gears of War 2.

We expect a huge drop next week (just as with Halo 3) but expect ODST to continue to do around 55-60% of Halo 3 sales at the same point from launch - so a good indicator for holiday sales will be to look at what Halo 3 did in 2007 and take off 45%. Based on this, ODST looks good for around 6 million in total sales - although the release of Halo: Reach next year will likely eat into any long-term sales potential that ODST may have.

Stick with VGChartz for all the latest updates on ODST sales.