I must be watching a different player, because I don't know what De Aza has done since coming up with the Sox last year that screams AAAA player? He's played in 79 games for us now over 2 years, has a .302/.379/.500 slash line, and his numbers extrapolate to 15 HR, 101 R, 31 stolen bases, 37 doubles, and 11 triples over the course of 162 games played. He's outperformed anyone's wildest expectations. On top of that, he's just a ****ing spark plug. He plays hard, seems to have a good baseball IQ (at the plate, anyway), and is just an exciting guy to watch. I definitely feel he brings an intangible energy to the team, like he's out to prove everyone who gave up on him wrong.
Now, granted, I know that he just turned 28 so you can't pencil him for the next 10+ years like you would a more traditional prospect, but his prime years will probably last until at least 2015.