Judas. Bad Romance is only so hyped because of its video. Its the same for MJ's thriller. I think Thriller (song) is the weakest song on the album and yet its his biggest because of the video. Not comparing Gaga to MJ here just using him as an example.
what made BR so memorable and epic was the amazing video it had... if JUDAS follows up with an amazing video it can definitely be better than bad romance.. so for right now i vote BR !