I traded Prince Fielder and Barry Zito for Paul Konerko and Johan Santana two weeks ago. I felt like Fielder was going to cool down (he had 17 HR's at the time), and Zito was too up and down for me. I felt like Konerko HAD to get better, and Santana was underachieving. I traded Fielder to a guy who i was playing head up the next week, and Fielder hit 4 or 5 homeruns against me after i traded him. I'm not sure if it was a bad trade, but it was definitely bad timing.
On a Chipper Jones note, some goofball in my league dropped him after the first week of the season....let's just say, he was probably my best waiver wire pickup so far.