Bad romance or The edge of glory hands down! Now if DITD was a single it'll just be too obvious lol
According to Ranking:
1st & 2nd (tie) Bad Romance or The Edge of Glory
3rd Poker Face
4th Paparazzi
5th Marry the Night
6th Born This Way
7th Alejandro
8th Judas
9th Just Dance
10th You and I
11th LoveGame
12th Telephone