Some of the biggest trades in Anaheim Ducks history have involved Chris Pronger. Oddly enough, the deal that brought Pronger to the Ducks in 2006, and the deal that took him out of Anaheim in 2009 both involved Joffrey Lupul. These two were very big trades, but any deal that wins a franchise a championship warrants the title of "best" trade.
In 2006, the Ducks made a blockbuster trade with the Edmonton Oilers:
2007 First-Round Pick - Nick Ross
2008 Second-Round Pick - Travis Hamonic
Conditional 2008 First-Round Pick - Jordan Eberle
Now, some may argue that Edmonton won this deal, but let's look a little further.
Edmonton, no doubt, acquired a real superstar in this deal. Not Lupul. Not Smid. Certainly not Ross or Hamonic. The real steal in this deal is and was Jordan Eberle. He is perhaps the most clutch performer in the entire league, and undoubtedly has an extremely bright future in this league, especially surrounded by a young team of superstars in Edmonton. He fits right in.
However, the other parts of the deal aren't as great. Smid is still with the Oilers, which I'm sure Edmonton is happy about. However, many hockey fans have never heard of Nick Ross. Travis Hamonic never played a game for the Oilers, as his draft pick was traded to the Islanders. And Joffrey Lupul only recorded 28 points in one season with the Oilers.
Anaheim, on the other hand, with the help of fantastic numbers from Pronger on the blue line, won a Stanley Cup.