Desean Jackson is the best punt returner right now in the NFL. And by best, I mean the most likely to take one to the house.
I suppose best could be the one that does everything well. Catches the ball cleanly, fair catches when appropriate, follows his blocks, keeps control of the ball etc, but I tend to think, who is capable of making the big play and that is Jackson. Remember this one against the Giants - http://www.youtube.com/watch?v=ZH0bh75JMxY