And the winner, by nearly 100,000 copies in the first month, is Beatles Rock Band! Following the release of NPD sales data for September, MTV Games general manager Scott Guthrie said to Gamasutra:

We outsold them two-to-one on a revenue basis and we outperformed on a unit basis as well, despite the fact that they had an eight-day advantage, and were giving away free software....At the end of the day, The Beatles: Rock Band clearly outperformed them, and we're not done yet. We're anticipating a very successful holiday period.

The total number of Beatles Rock Band copies sold was 595,000 for the Xbox 360, Playstation 3, and Wii. The total number of Guitar Hero 5 copies sold was 499,000 for the same three platforms as well as the Playstation 2.

Round two will be Lego Rock Band vs. Band Hero.