I was a huge fan of the Bill Walker pick. I still don't understand why he didn't work out.
I would've picked Oden over Durant, and no amount of revisionist history will make me reconsider this.
Amare Stoudemire, Andrew Bogut.
I didn't think Rondo would continue to get better.
I didn't think Jeff Green could ever elevate his game to the level he is at now. I still think he's overrated if people think he'll continue to improve.
Edit: also Michael Beasley, Yi Jianlian.