''Since its inception, Harmonix has emphasized that Rock Band is a music platform rather than a single game. Staying true to that rhetoric, Rock Band 1 and 2 are both fully cross-compatible. All previous downloadable content will be available for RB2, and all future DLC will be usable in RB1. You can even choose to import the Rock Band tracklist into Rock Band 2, copying all of the songs off of the CD onto your hard drive. As if that wasn't enough, Harmonix has also announced that between now and the fall they will release twenty free downloadable songs, all of them master recordings.
The Rock Band 2 tracklist reads like a veritable who's-who of the rock and roll world. Songs appear from artists such as AC/DC, Bob Dylan, Talking Heads, and Pearl Jam, and the game can even boast the world debut of a new Guns 'n Roses song from their upcoming album Chinese Democracy. Harmonix claims that there will be over 500 songs available by the end of the year, which is quite an impressive number; while competitor Guitar Hero: World Tour may be trying to win people over with shiny new features like the Music Creator, it is clear that Rock Band's draw will be its impressive and ever-expanding music library.''