I'm not a good singer, but I'm mostly around the 7500 points in medium mode (easy 8500pts)
What's weird is that I've around 8000points for Japenese/Chinese songs,
7500 for English songs, but I'm quite very bad with a lot of french songs
(It's my maternal language, and I sucks in it, like my lowest was 4950pts but don't remember which song).
My bests scores are (medium mode):
Linkin Park - Shadow of the day (~9700points)
Rie Tanaka - Fields of Hope (~9600points)
I don't remember exactly the score, but I know my sister did 9970pts for Shadow of the day.
I got quite some other songs around the 9000pts, but it's mostly around 8000pts