Dead or Not Dead

So ends the saga of Jake Peavy to the Cubs for 7 or more players. But is the deal really dead? In fact, even the Brian Roberts deal isn't exactly dead. These kind of non-transactions take a "life" of their own. So I thought we might play a little game. One of the more common cliche's is "the best trade is often the one not made". So I'm asking for you to reach back and see what you can remember as to rumored trades that never occurred but if they had been made, would have been one gigantic mistake for someone or maybe even a timeline changer in the course of baseball history. Sosa for Soriano circa 2000 comes to mind. I'm sure there are some good one's out there to remember. Please help.