Personally, I would like to see him fight the winner of Cotto/Margarito. It would be the most hypeable match. And a great way to keep Oscar fighting the best.

Here's how I think he would fair against everyone:

vs Cotto: Cotto by stoppage. Cotto would bust him up inside and be too strong/crafty. If he was able to hit Mosley at will, he would do a number on De La Hoya. Cotto can fight backing up and coming forward, southpaw and right-handed, he's just all around SCARY.

vs Margarito: This would be a better match up for Oscar than Cotto IMO. Margarito would take what Oscar has to give but return fire even worse. Margarito only knows how to go forward, but Oscar is a good counter-puncher so the style would mix very well. I wouldn't be surprised if Oscar won here though. But if Margarito gets past Cotto, I would pick him over De La Hoya.

vs Wright: Usually, I would pick Wright to box circles around De La Hoya, but due to his aging and inactivity, I see Oscar winning now. Give Winky a tune-up fight, then he wins a lopsided UD.

vs Shane Mosley: I don't think they should fight again. Shane can still compete with the best in his division. At this stage in their careers, I don't see much changing. Mosley UD.

vs Paul Williams: Williams is too active and too long for De La Hoya. Williams would make Oscar look bad.

vs Sergio Mora: Take this off the list! No one would want to see this! Oscar by UD though.

vs Steve Forbes: Just when I thought Mora would be the worst idea here, Forbes would be even worse.

At this stage in his career, Oscar would lose most of these fights. A prime De La Hoya, would be a different story. If he want's that final victory against a name, he should fight Pacquiao or Hatton. Everyone would think those fights as complete BS, but Oscar did fight Forbes so anything is possible with him.