Dave

I didn't realize Dave was imaginary - I should have picked up on that, but I just figured Hurley was hallucinating him on the island like Jack hallucinated his father, Kate hallucinated a horse, etc.  What's amazing to me is that Hurley hallucinated someone that he also hallucinated back in the real world!  So he really is or was a bit nuts. 
 
I loved the whole Henry thing - first when Sayid busted him for killing the real Henry Gale, that was great.  And then later when Locke was talking to him - when he said that God can't see the island, I had chills!

Oh and I also loved the Hurley/Sawyer smackdown!  How funny was it when Sawyer tried to crawl out from under the tarp and got pulled back in!  It was like a cartoon fight.

Good stuff all around.  Excellent job by Jorge Garcia as Hurley, and of course Dave was Evan Handler from Sex & the City!