MTV has said more than 2.5 million Rock Band songs have been downloaded from Live and PSN.
Developer Harmonix has added fresh content regularly since the game's US launch last November.
Songs can be downloaded in packs of three for 440 Microsoft Points (GBP 3.74) or USD 5.49 on PSN. Or you can buy them individually ranging from one to two dollars, depending on current offers.
Most popular so far is a Metallica pack with masters of Ride the Lightning, Blackened and Justice for all. The Police and David Bowie combination bundles (two covers, one master) also sold well.
The individual crown went to the Juke Box Hero cover by Foreigner, while Buddy Holly by Wheezer stood out as the only master among the runners-up.
Full album downloads will be out "very shortly" according to MTV boss Paul DeGooyer (talking to GameSpot), although a price is still to be mentioned.
He also promised standalone instruments "shortly", as currently you need to buy the entire bundle to play.
Rock Band was released on 20th November in the US, but recent NPD yearly sales figures showed rival Guitar Hero III was currently winning the rhythm-action battle.
The game won't face in Europe until sometime this quarter, but clever clogs Tom managed to get a US version to play and decided it was worth an 8/10. Pop over to our Rock Band review to find out why.