It's Pablo César Aimar.
You're probably confusing his names with Aston Villa's Angel's (Juan Pablo) who, by the way, played together with Aimar in River Plate. Back in the day, River had Aimar, Ortega, Saviola and Angel altogether in the lineup and they were called The Fantastic Four.
Anyway, if you are looking for an Aimar but cheaper, there's Leandro Romagnoli. In my opinion, he's even better, and he's only cheaper because he's still in our League and he doesn't get the coverage he would deserve, just because he's in San Lorenzo and not in Boca or River...
You don't believe me? You'll see for yourselves when I'm done with those highlight clips I promised. I hope our Webmaster will allow me to host them here...