Liverpool's and arguably one of the top three players in the world at least was originally signed by us btw.
The issue hasn't been identifying targets for the most part, but not putting up the fee being quoted or signing them once they're on the decline (Torres, Eto'o, Falcao & could throw Higuain in the mix too).
To me, the club's failure to sign Aguero was one of the biggest mistakes we've made in that regard.