I voted Xeyrius Williams. 5th(?) year senior with experience playing at this level.
For me, Greg Tribble and Camron Reece are tied for #2. X will make an immediate impact. But I think these two will be up to speed before conference play begins. I remember following Tribble's recruiting in high school. He's a serious talent. And Reece looks like a monster; our next Ultimate Warrior, a'la Jeremiah Wood or Demetrius Treadwell.
Then again, I don't think any of the above mentioned players will matter if our returning core doesn't improve their shooting percentage from behind the arc.