This is hard, but I would say Okafor. His rim protection skills were legendary and it is hard to find a player since Oakfor who can compare anywhere in the NCAAs. The thing is, even if he did not block a shot, he changed so many others and he opened up the floor on the offensive end. Plus he was an exemplary leader on and off the floor. He was a good sport, an excellent student, and a great person who led by example and worked very hard. Add Okafor to this team and they are a FF threat and Top 10 team.
Kemba would be better for the long term. He would take the younger guards under the wing like he did in real life during his tenure at UConn which would lead to years of success even after departure.
So one of those two.
If I can't pick a star and have to go with a role player, Rashad Anderson, easily.