Last year we got Massive Attack, Daft Punk, Kanye and Madonna added after the initial lineup. So let the guessing begin!
I haven't lost hope for Neutral Milk Hotel, Bowie, Prince, Velvet Underground, and Daft Punk because I didn't catch their full set last time. I'd be ok with the Police.
Oh and The Knife, Herbert, Goldfrapp or Matmos for the Sahara, though given they're not major acts it's a longshot by now
JAMC are a great addition, so is Manu Chao since you don't see him too often here in the States.
What are you hoping for? There's bound to be some kind of pop star added soon. I just hope it's not Gwen