According to a survey that was found over at Kotaku, the unannounced Rock Band sequel will feature "120 songs from the 60's, 70's, 80, 90's 00's". That includes "songs from gods of rock like AC/DC and many, many others."
What is more amazing then the idea of having TNT or Thunderstruck in the game is the idea that, if Harmonix is able to bring over DLC from the first game, I could have possibly over 400 songs in Rock Band 2. That possibility is just mind boggling. Activision may have a fight on their hands.