The last two years (I didn't watch the first AI) some themes were reused. I have some ideas for the themes they could use for the Top 12. Some of these themes (especially the ones with a specific group or singer) would be good for the later rounds, when we see the people who can sing well.

New Wave (80s music)
60s music
#1 hits
One-hit wonders
The Beatles
The Rolling Stones
Queen
Neil Diamond
British Invasion

I don't mind if anyone lists the same things I have. I'd like to hear what everyone else would like to see.

Billy Joel (again)
Michael Jackson

I agree with Brian and Jeff I would also add

50s
70s
80s
90s
60s
Elvis
Buddy Holly

Id like to see
Classic Rock (Aerosmith, Van Halen, AC/DC, The Doors, kind of music)
Elvis
Beatles
The Eagles

Id like to see
Classic Rock (Aerosmith, Van Halen, AC/DC, The Doors, kind of music)
Elvis
Beatles
The EaglesDitto to that too!

Motown 60s
Soft Rock 70s
Disco 80s

TVGuide said thats some of the themes.