Good for her! She has such a huge catalog of songs that I guess there's not really one song most people go with, but plenty that most people know.
Really funn y about the top 3 though. ヘビーローテーション is the number one song and it's also the song I've sung the most at karaoke
Not only that, but ミスター and Gee are probably my second most sung. Very cool :O