As alraedy stated in the Manga, Kabuto is after Sasuke Uchiha. This will be because of what he did too Orochimaru. Along with this, I personally think (this isn't taken from manga) Kabuto will have Orochimaru's body switching technique, and Kabuto will switch into Sasuke's body, along with the white snake powers. This means; Kabuto will have both the white snake powers, orochimaru's powers, and sasuke uchiha's powers.
So basically, Kabuto is after sasuke as a vessel.