Here's the full list.
One Direction - Hate them, but no bigger pop act around today.
Bob Geldof - A given
Sinead O'Connor - Huge. Amazing.
Ed Sheeran - Massive. Very good.
Ellie Goulding - Big. Very good
Sam Smith - Very "now" and very good.
Rita Ora - Didn't know who she was until I googled...