I don't think I will be able to come up with ten singers even if I combine Rock and Pop :-\

Only rock? I think I'll mix it with pop (well you did too)

1.Trent Reznor
2.Jon Bon Jovi
3.Adam Levine (Maroon 5)
4.Tuomas Holopainen (Nightwish)
5.Brian Molko
6.Chris Martin (Coldplay)
7.Robbie Williams (does Robbie also count?)
8. Ville Vallo (I don't like HIM much but Ville Vallo looks good)