Ah well, Cohen is special case. Can't compare him.
Songs of Leonard Cohen and Songs from a Room are still his best albums, imho.
As for Billy Idol, to be honest, only things remember are Rebel Yell, Dancing with Myself, White Wedding and.. can't remeber the rest, really. I was 4 just years old then.
He was quite rad indeed at the start of the '80's, but isn't so representative of later developements. That said, his music videos are as atrocious as they came at the time.