I say that Fergalicious (featuring Will.i.am) by Fergie is the worst self-referential song. My wife says that Everybody Have Fun Tonight by Wang Chung is the worst.

Lyrics from Fergalicious:

I’m Fergalicious (so delicious)
My body stay vicious
I be up in the gym just working on my fitness
He’s my witness (oooh wee)
I put yo’ boy on rock rock
And he be lining down the block just to watch what I got (four, tres, two, uno)

Lyrics from Everybody Have Fun Tonight:

Everybody have fun tonight
Everybody have fun tonight
Everybody Wang Chung tonight
Everybody have fun tonight
Everybody Wang Chung tonight
Everybody have fun