There are 3 tied for the best move I've ever made.
1. Last May I traded D Lee and R Harden for Roy Halladay and D Wright. This was when Halladay had just had the appendectomy, (or whatever it was he had), and Harden was "about to come off the DL", and Wright was still in his early season slump!!
2. Last year I claimed R Braun off waivers in 2 leagues!!
Won 1 and finished #1 seed in other and lost in finals!!
3. In 2004 I claimed B Sheets off waivers before the season started. Won that league as well!!
I could go on and on, but those 3 were probably the best and had the biggest impacts on each season.