Whoa, I hope it is happening. Last year's line-up was good, but I wasn't able to make it. I'd definitely go this year to see NIN.
30 Seconds to Mars was on Lollapalooza last year. That would be great if they got on it again this year to promote their new album. And I bet 30STM would love touring with NIN since NIN was an influence of 30STM.