I'm still thinking it will be Ke$ha's new single. I just get the feeling it will blow people away. Also, Nicki has a range of potential smashes that she could release. The Rita Ora song will hopefully do well too.
Some Nights
Where Have You Been Night of My Life by Pauly D
I'd say WHYB, it's just begging to be released so it can smash. With a hot video and good promo I can see it topping the charts for multiple weeks. But who knows, it's probably going to be a song none of us expect or still haven't heard yet.