You really can't single any out, they were all such good wins in their own ways. But if I HAD to really pick one, and that's if a gun was pointed to my head - I'd choose the DeMarco win. It was just so top tier at that time.
He shouldn't have even had the welterweight title. Paulie was robbed. I would have liked to see Malignaggi-Mayweather. Malignaggi is a great boxer. He fought for the light welter title against a guy who wasn't even in the top 10. They might as well have just handed him the title instead of wasting our time. I only count the sfw and lw titles he won. So to me he is a 2 weight champ. Very unimpressive when fighting guys his own size as lightwelter and welter. Unless he can seriously turn his career around he won't be remembered as anything other than the loudmouth that Maidana shut up.
Rees? It's ridiculous that he ever became a world champion really. I mean full respect to the guy but it does show how lucky a fighter can be in the world title stakes. Some guys who would have battered Rees from pillar to post have never even challenged for a world title IMO.