KO1 Juan Nazario was a bit unexpected, and definitely one of the stand out moments of the decade for me. Nazario had just stopped Rosario who had a bit of a hex over him and had gone 8-0 since that brave effort against Chavez. Crazy stuff really.
I would say the two fights against Jose Luis Ramirez, including the "loss." I would also include the easy decision over Azumah Nelson and surprisingly competitive fight against Freddy Pendleton.
His fight with Anthony Jones should also be mentioned. Showed some really good offensive skills and threw about 800 punches and scoring 50 percent of his shots.
I'm with LittleRed. The Haugen fight. Whitaker at his flawless best. Haugen was a very good, and very crafty fighter. Whitaker made him look like a totally inept caveman for 12 rounds.
In terms of just demonstrating how utterly, utterly brilliant Pea was at his peak, it's the Haugen, Ramirez (II) and Nazario fights. In terms of good action and fights which were fun to watch, it's Uncle Roger or Paez.