GH4. You can just recreate the RB2 songs with the song creator, not to mention your own. Besides, GH4 will kick ass because Harmonix was INSPIRED by GH. Ever see the companies that made GH3? Harmonix split after making GH3 with Red Octane because they thought they kicked ass. They failed at making a better one, and even by RB10, which will never come out, it will STILL not be as cool as any of the GH games, besides that crappy "air guitar" one that I have seen.