to have Tiger Army on this game would be siic!! they have good music and fun songs to sing. Id suggest Cupids Victim, Forever Fades Away, Wander Alone, True Romance, and Nocturnal. Those 5 are great songs by Tiger Army and would be fun to play in Rock Band.
Number of the Beast and Run to the Hills are great Iron Maiden songs but if they had Hallowed Be Thy Name and The Wickerman it'd be even better.
A few good AFI songs to have are Sing the Sorrow, Death of Seasons, Bleed Black, and Ever and a Day.
Yeah they already have Metallica songs on the game and for download but they should have Whiplash, Master of Puppets, Metal Militia, and even Nothing Else Matters.
let me know what you think.