the more I think about it, the more I'm tied between Unusual You & Kill the Lights
I think Unusual You does sound kinda summer-ish.... so maybe it would do good if it were released around June / July
However, Kill the Lights would be a nice, upbeat summer smash.... plus, it would be funny for people to hear the beginning of the song ("Ladies and gentlemen we interrupt this program of dance music to bring you..... etc.") and people think that War of the Worlds is being broadcast again!
.... only to realize that it's Britney.