Gangnam Style - PSY
Moskau - Dschinghis Khan
Love Love Love - Jolin Tsai
Ven Ven Ven - Sex Bomb
Sex Bomb's inclusion in this list might raise some eyebrows, but why not include Spanish music in this list? The song is definitely danceable, the music video provides some moves to incorporate, and the tune is catchy enough that it will get thoroughly stuck in the minds of anyone who plays it.
Dreams Come True - SES
While this may be one too many Korean songs, SES cannot be overlooked. "Dreams Come True" is a true classic kpop song, and really, really, REALLY should be included.
So...Harmonix? If any of you read this, you should definitely work these into your game at some point. You may already have an awesome song lineup, but including these songs as DLC would be totally awesome.