Parker.
He just seems to have "it" to me. I think he'll come into the league and immediately be one of the better scorers at this position, and he'll rebound well. The defense and passing will be a work in progress.
Drafting him would solve the biggest problem for this team's rebuilding effort, which is finding that central focus for the offense.
Embiid would be my next choice, because he would solve the other major problem, which is finding a defensive anchor with good size.
Getting either of those guys would make the challenge of rebuilding this team into a highly competitive group a heck of a lot easier.
I still believe in Wiggins, too, but I think he may be more of a "do a little of everything and dominate with athleticism" sort of player, especially at first.