I have a few recent ones which I think may be good but too soon to tell.
When I first joined this league, though, I tried to remake my roster whch sucked. One owner really wanted Adalius Thomas, who just left Baltimore for NEP. I ended up giving Adalius Thomas for Eric Barton, 2008 2nd & 5th round picks, and a 2009 1st round pick.
On a whole, I think the trade was a big win, considering Barton was significantly cheaper than THomas and outscored him 191-162 over the past two seasons... but the best part are the moves that this enabled afterwards.
First, I freed up cap space which I was able to use to acquire Tuck and Cromartie who were both UFA before their breakout seasons. In the 2008 draft, I took Curtis Lofton with that 2nd round pick and Xavier Adibi with the 5th round pick. Later in 2008, I traded Lofton + that 1st rounder (I now had 3 2009 1sts) + my 2011 1st for Matt Ryan. Then I traded Adibi + 2.04 for Lofton + 2.11.
So, through some level of indirection, Adalius Thomas turned into Barton, Lofton, and Matt Ryan - and at some level Tuck and Cromartie.
More recently, I sold Kevin Smith for a 2010 1st and 2nd, and 2011 1st, 2nd and 3rd... to a team that should be pretty bad. I'm a big fan of Smith's, but I think that could turn out pretty well for me.